Anti-German (German: Antideutsch) is the generic name applied to a variety of theoretical and political tendencies within the left mainly in Germany and Austria. The Anti-Germans form one of the main camps within the broader Antifa movement, alongside the Anti-Zionist anti-imperialists, after the two currents split between the 1990s and the early 2000s as a result of their diverging views on Israel. The anti-Germans are a fringe movement within the German left: In 2006 Deutsche Welle estimated the number of anti-Germans to be between 500 and 3,000. The basic standpoint of the anti-Germans includes opposition to German nationalism, a critique of mainstream left anti-capitalist views, which are thought to be simplistic and structurally antisemitic, and a critique of antisemitism, which is considered to be deeply rooted in German cultural history. As a result of this analysis of antisemitism, support for Israel and opposition to Anti-Zionism is a primary unifying factor of the anti-German movement. The critical theory of Theodor Adorno and Max Horkheimer is often cited by anti-German theorists.
Antideutsche are normally what happens when you try to become a radical leftist with no theoretical foundation besides what you learn in highschool. They're extremely dedicated to anti-fascism, but entirely incapable of understanding the historic and material context of its rise and the real world implications of being a committed antifascist. Due to their lib brainworms, they have a strong tendency to stan the USA und UK for defeating Hitler, but will not extend the same carte blanche to the USSR, as once more, they are dumbasses who don't read theory and try to synthesize leftism entirely from the center-left mainstream liberalisms they've picked up along the way. It's fairly generous to assume they've read any Adorno, usually they are too busy picking fistfights with anti-imps to do any reading. Completely brainwormed and 1000% guaranteed to have been actively encouraged and built up by the VS to split the left.
As fringe as they are, they are vastly overrepresented in the public perception of antifa, and a huge influence on Germany's biggest wannabe leftist newspaper, the taz (that's the one with the transphobic boomer gay nest, and yes, Jan Feddersen, the head transphobe there has an antideutsche background as well, but at least he had to tone down his anti-trans bigottry after a trans guy was murdered at pride last year).
Is wrong on multiple levels.
Antideutsche is also a wide umbrella term now and it makes sense to separate specific groups at specific times and general though of Antideutsche.
Plenty of Antideutsche though leaders of the late 90s have had a lot of university education, not rarely including PhDs and also in some cases were still thought by GDR, or Soviet educators or even had cadre schooling by organs of the state (most didn't though and especially after 2000 not).
I agree that they have a very strong focus on anti-fascism and I did stood with people who would label them like that against fascists in the 90s. However some people who were on the street with us did develop into directions that conform to some of your descriptions.
I will not go into structures and names, but instead describe a bit the situation of the emergence of Antideutsche in Germany.
The time period is the beginning of the end of the GDR, the wall fell, the German states would reunify, first demonstrations against Germany after that in Berlin would be clubbed by both police officers of the FRG s well as those of the former GDR. Never again Germany!.
Those demonstrations were antifascist, were against antisemitism, were anti imperialist and had seeds of internationalist orientation in them.
The years after the end of the GDR the lack of state power create a vacuum in the "Neue Länder" the "new states", which meant that the right wing and the extremism of the center was strong. Combined with a lack of jobs, no infrastructure but plenty of spaces to fuck around meant creativity could be born (like squatting military areas and create festivals), but also that violent Nazis and racists would be free to dish out violence. The time period is called "Die Baseballschlägerjahre" by antifascists "The baseball bat years" as that is what Nazis during that time often walked around with. Plenty of people who don't fit the main stream right wing political opinion were assaulted, injured, killed, sexually assaulted etc. with the state not doing much and the police often not being your ally, but instead would repress you some more. This meant that a need for self organizing was essential. I am very thankful for all the antifascists of that time period as "Antifascist self defense" really was what made spaces more safe, not the state. However the power of violence was very obvious during that time.
At the same time the Left in Western Germany or what was the FRG lacked organization and with the fall of the GDR often broke off, the "End of History" was very influential and plenty of people would be outed over the next years as having worked with the GDR or the MfS (Stasi/GDR intelligence). This meant that more autonomous leftist groups would come into the forefront. A side effect of those processes was that the Western left mostly sucked at helping comrades in the former GDR and also had a ton of (liberal) disagreements with them or arguments about purity. This meant that it was often intuitively understood that sometimes you would get help from the Left of the West, but you would have to deal with shit on your own and that safety of you, or marginalized groups would not be guaranteed by the state or your allies in the West, but by people with power.
Remember during that time 20-30 people per year would be killed by the right without repercussions and the state often times ignoring that, they could hunt people openly on the street and if you were somewhat left or antifascists you would know personally people who were assaulted.
With stuff like the pogrom of Rostock Lichtenhagen by the centre, Nazis and such against people that sometimes had a background as migrant workers from the socialist fraternal state of North Vietnam (but often not), a police force which didn't do shit for days except for repressing antifascists and the state removing the basic right to asylum from the basic law and reintroducing it in a form of a wet rag were events that closely followed.
Shortly before that there was an inner left conflict about the Gulf war, which lead to the heightened conflict between Antiimps (anti imperialists) and AntiDeutsche.
I will not go into the theoretical parts as others did that more informed and better, but at least from what I witnessed during that time the conflict often was on practical terms and the brainwormed intellectualized Bahamas stuff came later. Practical terms as: Seeing that during Rostock and alike the Left was not able to defend people on German ground and seeing that Jews weren't safe in Germany doesn't it make sense as country of Auschwitz to focus Antifascism (as Nazis were the people who would assault you in any case if police wouldn't) and the fight against antisemitism? Antisemitism in the left was a huge deal during that time and intersectionality rare. Sure in theoretical organs the fight was not that much about practicability in Brandenburg at least it kinda was. Were the majority of actions against antisemitism actually doing stuff against antisemitism? Wouldn't want to judge, but there are good reasons to be somewhat critical.
However those founding seeds of the Antideutsche movement are 20-30 years old and the developments afterwards are not based on the same social conditions. So what can be said for 2010 and later is that Antideutsche have little impact on the Left except in margins and that antisemitism in the Left remains a problem.
What can be said is that popular in the sense of known Antideutsche thought leaders are close to very right positions i.e. transphobia. However for Leftists "Expats" (as in form Western countries) in Germany it isn't uncommon to freely label Leftists they don't agree with as Antideutsche. Which is said, cause most people aren't Antideutsche and it kinda hides what is really going on (often lack of theoretical knowledge as OP said, lack of practice, but sometimes more awareness of Antisemitism than people from the US).
This isn't the truth, but I would like people to understand more the vibes people had when stuff was created. Still a lot of reactionary stuff was created by prominent Antideutsche.
Without the fall of the Soviet Union or without reunification no Antideutsche.
What do you mean by antisemitism on the left? What form did it take and how were anti imperialists part of it?
Those are two very different questions. Antisemitism on the left at that time could include stuff like:
philosemitism
reductive/regressive Marxism "the Jews are merchants therefore not a productive class" and therefore not workers
denial of continuity between repression before 1945 and after
ignoring jewish victims
within the Left (that was earlier, but there is a continuity, the RAF selected jewish from non jewish passengers during air plane kidnappings which is a bad look) selecting which Jew is good and which not
the regular antisemitism and antisemitic stereotypes
"the jews always make trouble" was something I did not seldomly hear from left people even organized Marxists
complete disregard for Jewish life in general and in Germany specifically
judging main contradictions of capitalism to be more important than the "Jewish question"
ignoring Jewish positions and completely disregarding Jewish socialists in Israel
accepting to work together with people that aren't only anti zionist, but openly antisemitic including with people that do holocaust denial, etc.
(added) of course the acting as if Jews are homogeneous belongs on the list, too
To name a few. Disregard for safety of Jews that emigrated, too. Where is after the fall of the Soviet Union a safe place for Jews? Certainly it wasn't Germany.
Disclaimer: Anti-Imp is a label, not a true description of the groups.