What?

when beehaw famously defederated from lemmy.world ages ago, as well as sh.itjust.works

They've been defederated from lemmy.ml, lemmygrad and hexbear for much longer though.

while the admin of lemm.ee has said, controversially for some of their users I believe, that they don't really understand all of the fuss over hexbear.

I guess that explains the heavy Tankie presence on that instance, which I've negatively noticed as well.

I'm not sure what your point here regarding Beehaw is though.

Meanwhile, lemmy.ml tries to stay widely federated AFAICT, and from what I've gathered, the admins have even gotten in hot water with their lefty users for not defederating from more right-wing-ish instances earlier, and then are often criticised for their active moderation on their own instance.

And here you lost me completely. What right-wing-ish instances are we talking about? Because I have yet to see anything that even mildly steers into that direction. And what moderation? Banning non far left positions and those who talk back against far left disinformation? Just look at their news sub and how much mod abuse & disinformation there is. Tankies can freely insult people and the mods do absolutely nothing. Correct disinformation and you get banned. If that's an issue for the admins, then they could actually do something about it, since they literally own that instance.

and don't like what they perceive to be a culture of demanding open source users (which I've come to understand over time actually).

"Demanding open source users" is a nice way of framing community demands negatively. lol