I think this is a complicated example because although at times Marxists and Islamists made common cause, Islamists were also a very effective weapon against communists, such as in Palestine, Afghanistan, Iraq, Iran, Yemen, etc.

I am begging you to think about this dialectically. Obviously, I am not saying "Islamists are good friends to Marxists". Generally, I would hold the opposite to be true. That having been said, we can see today in Palestine and sometimes other places that MLs and Islamists can work together quite well when they have a common enemy that they oppose more than each other. Even in the best of circumstances, it is a partnership that will end in bloodshed as they turn on each other following the hypothetical defeat of their colonial oppressors, but for a stretch of time it works quite well.

Exactly this is what I am saying of the anarchists and Marxists in, for example, America. Perhaps it will come to an end that one or the other won't like, but if an anarchist thinks it is more worth it to fight muh tankies than to join hands with them to fight fascists, they are smoking crack.

I don't think the Zapatistas or Rojava are clear examples, or at a large scale.

Rojava is worth mentioning but Zapatistas, in the main, aren't anarchists and vociferously object to such a label.

And yet there's comparatively successful political coalitions that involve both socdems and communist parties. I'm thinking particularly in South America. China and the DPRK have sanctioned liberal/socdem parties, but I don't believe anarchist organizations are permitted. I mean, many social democrats see themselves as reformist socialists or Marxists of some stripe. And third world social democracy seems very different from imperial core socdems, but we don't have to qualify socdems as "western socdems" to criticize th

Part of the issue here is the simple inadequacy of anarchism with large-scale organizing and its natural opposition to compromise. What do you expect the PRC to do that would allow a show-and-tell anarchist to feel satisfied? To have a little commune or syndicate? But then mustn't such an entity be beholden to laws at a higher level, in both a theoretical and practical sense, to not just be a liability to the state and a cult-in-the-waiting? Doesn't sound very horizontal to me!

Of course, what I would consider a serious anarchist is someone who supports the revolution that feeds the children while pushing in the direction of horizontality, and by such a definition surely they should be happy with the implementation of, for example, the Tae-an farming system in the DPRK. But one who it more interested in spreading a religion of anarchism, to whom feeding the children with any verticality involved is an insidious deception, the fact that those collectives still must answer to the state means that any virtue they have is farcical.

Your sectarianism is my tolerance paradox, I guess, and it's indeed part of the insidiousness of capital that it's quite willing to compromise when it needs to.

"Socdem" is a difficult term to use the way you've expressed it because the term has a long and varied history with many offshoots in usage. The way that HB usually phrases it is that the people you just identified are in large part actually demsoc, and I think that phrasing is fair. One could also argue that the true dividing line is if the so-called demsoc believes revolution isn't the best strategy, or would actually oppose revolution should it appear seriously viable, with the uprising already underway.