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.
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.