This is really interesting. I wonder, would it be useful to start framing things more as "I have observed X in fandom"? It still creates a slightly misleading impression of fandom as a semi-unified whole, but saying that X appears to exist within fandom seems less flattening than saying fandom simply does X. Plus it leaves space for those fuzzy situations when you have observed something in a variety of fannish spaces and you want to point out that this trend seems widespread to you, without getting into every single possible caveat about fandoms you may or may not be familiar with. I feel like the framing of observation definitely gets one's limited POV across, and provides space for people to say, "but I have observed Y which contradicts you/coexists peacefully/represents an interpretation you have perhaps overlooked/etc." without necessarily feeling like one has tried to speak for them.

You can also go on from your observations to argue that you have also perhaps felt X yourself, and make further more auto-biographical comments, so it's not like it's necessarily a pose of objectivity or separation.

On the other hand, I also think having a ton more straight-up "this is how fandom works for me personally" posts would be great too, and that people really would be interested, so if fandom conversations shifted more to that framing, I think it could work just fine as well.