There are going to be people you encounter online who say the most wild things, who can twist your words into an attack no matter what you do, who will lie, and yell, and encourage harrassment. No matter what you do or who you are, your words are problematic to them- You're ableist, transphobic, racist, sanist, etc.
If they can't find fault in your words they will poke and poke until they get something to point at and say 'look, this is a bad person, I was right!' Nevermind if they've done and said the exact same things, social justice for me but not for thee. Hypocrisy is not in their vocabulary other than to turn it against the Enemy of the Day.
I'm not talking about your run-of-the-mill troll doing it for a laugh. Usually it is someone with real skin in the game, someone who has been hurt and is still hurting and only knows how to deal with it by taking it out on others. They generally respond very poorly to expressions of concern or suggestions for alternatives to what they're currently doing.
It sucks because clearly they are having an awful time, and often they gain an audience that feeds off the high of each new fight. They excommunicate anyone that isn't in full support so it becomes an echo chamber.
They generally have a long standing pattern of ruminating about a certain discourse or Enemy of the Day and bringing it back up, juggling their discourses every few days/weeks/months to keep the intensity high even when everyone else has gotten sick of it.
If this description resonates about anyone you've seen, I suggest ignoring and blocking from the get-go, do not interact, do not express concern, if you have them blocked and they are fomenting about you still do not respond to anything they say, delete all asks regarding it, turn off asks for a bit if you need to, let the wave pass.
We all want to defend ourselves, our morals, and our community. But any interaction at all feeds the cycle they are in. If you are worried for them the best thing you can do is leave them alone. I think that it's kinda cruel how the internet makes this sort of person (who is obviously hurting badly and struggling whether they agree or not) into a spectacle.