"Hate" speech doesn't exist in the USA, it's protected speech. There was a Supreme Court decision regarding this a while back.
Should Apple be sued for not removing FB?
It's a lawsuit by an activist group. No indication of any grounds for the suit or that a court will entertain it.
I hope Apple does not give in to this PR campaign (which is what it is). If they do, Signal is next. Everything they're saying about Telegram groups (not public channels) applies pretty much equally to Signal groups.