Why has this forum become so slow?

Regardless of politics, doesn't it worry you that social media are now censored? I don't use any of them.

Another concern I would have, is that (I think) there is no way to use them anonymously using a pseudonym, as most people here do.

As I mentioned elsewhere, I tend to use a different username on every website or forum. The obvious exception is continuity between here and a previous forum. This applies on social media too. I don't use my real name there. And I don't use the same pseudonym twice. These days I consider real names as too valuable to hand out like free candy-bars to all comers. Close real-world friends know who I am. Online its a different game.

The algorithm that decides whether what I post here might be of interest to someone else I know, would be totally opaque.

Sorry, I don't understand what it is you are meaning here.