Consider the ActivityPub Fediverse. With notable, short-lived exceptions (when a bad actor shows up with a new technique), the majority of the abuse comes from a handful of instances, whose administrators are generally either negligent or complicit.
It seems far too risky to sign up on a service for the purpose of intercommunication that is able (or even likely) to burn bridges with another for any reason at any time. In the end people will just accumulate on 2 or 3 big providers and then you have pseudo-federation anyway.
"People will just accumulate on 2 or 3 big providers" is far from an inevitable circumstance, but there are conditions that make it more likely. That, too, is largely down to negligence or malice (but less so than the abusive communications problem).
Is that still true? As the admin of a small instance, I find the abuse coming from mastodon.social has been really low for a few years. There is the occasional spammer, but they often deal with it as quickly as I do.
However all the LGBT+ friendly servers federate with each other and that's good enough for me. I like not having to see toxicity, there's too much of it in the world already.
But I have not seen that outside the scope of Germany.
I don't know pleroma though. I've always hated twitter for its short-form content (I feel like it stimulates stupid nonsense like "look at my run today" and "I just had dinner" and discourages actual interesting content. So I was never into twitter clones either. I do use lemmy more although it has its own specific attitude issues around its developers (tankies).
Pleroma is Mastodon server software. For a bunch of essentially random reasons, it was popular among right-wingers setting up their Mastodon instances, and some servers responded by blocking any Mastodon server running it outright. A subset of those would also block any server not blocking Pleroma like they do.
Yeah. In practice, Fediverse servers have formed clusters based on shared values. And since the second-largest cluster is (iirc) a Japanese CSAM distribution network, everyone is very glad that this sort of de facto censorship is possible. Do you have a viable alternative?