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?
There was no red scare for anarchism, so it's much easier to go from liberal -> anarchist than it is to go liberal -> communist. If you take the former route, the propaganda around communism never truly fads. Also doesn't help that anarchists are typically the most active block of organizers/protestors/activists in the states. Communist orgs a lot of the time are just glorified book clubs, if you want to feed people, build bus benches, do a coat drive, counter-protest police, or whatever else, the people who are often at the forefront of this are anarchists. There is absolutely an image of the "academic communist" too concerned this theory specifics and sectarian lines to do any real action. This stereotype is rooted in some level of truth. I became disillusioned with anarchism, remaining steadfast that a vanguard party is key to true revolutionary change, yet in my own circles and among those I organize with, the communists in that camp simply do not organize, they do not. If you need advice on what book to read? They are the people to go to. If you need advice on mobilizing your neighborhood? You go to the anarchists. When I speak with communists I'm met with defeatism and often, an inflated sense of self-superiority. What is theory without practice? and to the anarchists: What is practice without theory?
It wasn't always this way, and it doesn't have to be this way. In the States there's no doubt that our synthesis of theory and material conditions will be a blend of both camps.
I consider myself to be something of an anarchist, if mostly aspirationally, and I think you've crystallized something I've had a hard time putting my finger on. All the irl self-described communists I've met, or even socialists for that matter, spend a lot more time concerned about theory than actually improving material conditions for those around them.
It's always the anarchists, even if they don't actually call themselves that, that are actually doing the thing.
I don't hate communists, our ultimate goals align, I might disagree with the path to get there at times, but we are aligned on outcomes.