My two cents on how to achieve left unity:
Anarchists: Stop using the word tankie. It pushes your fellow leftists away and pisses them off. Instead make specific criticisms of communist countries. ESPECIALLY stop calling MLs “red fash”. There is already enough misinformation going around about fascism.
Marxist-Leninists: Embrace critical support. Be willing to criticize and accept criticism of nations like China, the Soviet Union, and especially North Korea. Remember that being against US imperialism is not the only thing that makes a country good.
It really is that simple. The second someone brings up the fact that (AutHoRiTarIan ReGimE) did something right, you've got all sorts of nerds crawling out of the woodwork to tut tut some imperfect revolution.
Revolution is messy and "authoritarian" and ignoring that is silly. What isn't silly is understanding the historical context within which these revolutions occurred and doing our best to learn from history.
I'm fucking sick of hearing about your pet issue with early 20th century wars, and I'm doubly sick of hearing white people tell me that "everything would be fine if we just got rid of the current iteration of the dominant state" while conveniently ignoring most third world revolutions