It’s a compound word of fediverse and Reddit.

Stupid decisions by Reddit caused people to leave and search for an alternative.

Concerning the karma farmers and other spam bots: A lot of active redditors who reported them as soon as they cropped up aren’t on the platform at the moment. And some people might make use of ‘the troubles’ to set up new bots or for promotion. The last I’ve seen of those (before blackout) were people gifting karma/coordinate upvotes via subs somehow affiliated with Temu (some newish cheap shopping platform).