Fandoms are just inherently bad things, there's no real way to avoid them.
They're built as groups of people whose literal *only* connection is that they both like [thing]. The entire relationship between Fan A and Fan B is their mutual appreciation of [thing], therefore every interaction between them depends on [thing].
And here's the problem - no matter what [thing] is, there's only so much content for conversations to happen about. Even a massive franchise like Star Wars runs out eventually. Something like Rick and Morty has considerably less. If [thing] is your favorite sports team, there's only a few dozen seasons at most to discuss. Eventually, you're going to be having the same conversations (best trilogy? favorite Rick theory? is MJ or LBJ the goat?) over and over again; when you're only interacting with others in the same fandom, it's just one big feedback loop.
So therefore you have interactions only about one thing, and that one thing is inherently narrow in scope. Everything amplifies to unbearable levels.
I challenge someone to think of 1 (one) fandom that isn't annoying when taken on its own.