One thing I haven’t seen mentioned yet is that Mbin supports custom magazine/community CSS like Old Reddit did. Don’t think it’s federated currently though, so it’s local only. There’s also the ability to follow users and boost (retweet) content, which Lemmy lacks.
Judging by recent posts by Piefed’s creator, they seem to be planning to add end-to-end encryption and ephemeral content.
They’re referring to hate speech.
They’re not technically wrong, it is censorship and illegal speech to outlaw hate speech. But it takes malicious selfishness and a lack of empathy to actually take issue with it imo.