Yeah, switching from reddit to lemmy gives a "old internet" wibe: actual people, most of them technically inclined. But with more adoption, these people get diluted by all other kinds of folks.
Same happened with cypto scene. It started with cythography entusiasts, but now it is mostly tech bros.
It's easy to avoid redditization: just stay away from the "general interest" instances because reddit or facebook will always do general interest better than any platform run by volunteers w almost no budget.
Pick a smaller, focused website and focus on Local. Then you can ignore what's going on elsewhere.
Lemmy isn't a community, it's a technology. And ActivityPub is madw with the goal of letting anyone and everyone use it and participate. Just like HTTP. Griping because "the wrong kind of people are showing up" is the kind of thing the wrong kind of people do.
You don't get to build your gate in the public square.
Post passive aggressive notes as often as you can, make big honking stinkin posts screaming about the injustice, and eventually make a new community on a different instance, I guess. Just from observational experience.