Edit for clarity: I'm not asking why the Tankie/Anarchist grudge exist. I'm curious about what information sources - mentors, friends, books, TV, cultural osmosis, conveys that information to people. Where do individuals encounter this information and how does it become important to them. It's an anthropology question about a contemporary culture rather than a question about the history of leftism.
I've been thinking about this a bit lately. Newly minted Anarchists have to learn to hate Lenin and Stalin and whoever else they have a grudge against. They have to encounter some materials or teacher who teaches them "Yeah these guys, you have to hate these guys and it has to be super-personal like they kicked your dog. You have to be extremely angry about it and treat anyone who doesn't disavow them as though they're literally going to kill you."
Like there's some process of enculturation there, of being brought in to the culture of anarchism, and there's a process where anarchists learn this thing that all (most?) anarchists know and agree on.
Idk, just anthropology brain anthropologying. Cause like if someone or something didn't teach you this why would you care so much?
https://en.m.wikipedia.org/wiki/Kronstadt_rebellion
https://en.m.wikipedia.org/wiki/Emma_Goldman
https://en.m.wikipedia.org/wiki/My_Disillusionment_in_Russia
Having read My Disillusionment with Russia after learning how genocidal the war against the Soviets was and how stretched thin all aspects of society were due to the breakdown of economy, Emma Goldman unfortunately comes off as an extremely embarrassing American who can't stop expecting everything to revolve around her. It also goes unmentioned in her account how many of the anarchist cells that were being "purged" were openly destroying and murdering the emerging Soviet state, this would be unacceptable anywhere and especially because this emerging Soviet state was exactly what was needed to end the economic crisis.
The conditions the Soviets made their revolution under was harsh and unfortunately necessitated the decisions made later on, but they should be critiqued with the context in mind or else we're failing to learn from their successes and failures. When we apply our own context and preconceived notions onto a revolution which happened over a hundred years ago we are unable to take anything meaningful away except the most basic and propagandistic things.
Being frankly honest, this is just the history of reprisal and counter reprisal starting from the Russian revolution. If you read my post here and look into the history of the Russian civil war, it's very plainly spelled out.
The Bolsheviks criminalized this as wrecking which allowed them to propagandize future Marxist-Leninists against understanding a more neutral version of the history of conflict between the two groups. Many anarchists feel exactly what you describe here about the Bolsheviks actions towards Maknovischina during the Revolution -- the only real difference is that the Bolsheviks were successful at snuffing them out.