My guess is that a good portion of that comes down to the quality and breadth (or lack thereof) of the Lemmy built-in moderation tools. Combined with volunteer moderation and a presidential election year in the US, and I’m sure the moderation load is close to overwhelming and they don’t really have the tools they need to be more sophisticated or efficient about it.

I completely agree. I have a whole mini-essay that I’ve been meaning to write about this, about problems of incentives and social contracts on Lemmy-style servers in the fediverse that I think lead to a lot of these issues that keep cropping up.