Great post. I totally agree. I've only ever been in Western live-action TV fandoms, and even so, whenever I read or see implied or overt "this is how [specific or general] fandom is" stuff, it makes me feel like I don't count or I'm doing fandom wrong, and then I hunker down even more into my little oddball space. I can only imagine how much more alienating it would be if I came from significantly different kinds of fannish arenas.

How do you avoid it yourself?

I speak for myself.