As an update to the 'banned from AgainstHateSubreddits' drama, I just found out that the mods for that sub are predominantly Satanists, religiously. And I don't mean modern Satanists who believe in self improvement and reliance, I mean they lean heavily into the iconography of Hail Satan and upside down crosses like edgy edgelords. Which explains a lot. I no longer feel like it was a matter of 'me not being a leftist', it was a more a matter of them being unbalanced, biased individuals.
All is right with the world.