That wasn't what his original twitter rant was about though. His original rant was about YTers being overpaid and overrated, then this "someone threatened my family" claim was after that all blew up.
It isn't at all clear what started all this, but the claim of threats/actual threats was the end of it.
Having watched a lot of Gerald Undone's videos, I have a very very hard time imagining how he could incite anyone to threaten someones family. But I don't know the backstory, just saw the meltdown.
There are lots of people, especially YouTube commentators who will rush to attack anyone who is seemed to have hated on their favourite creator. It doesn’t matter who started what, it ended with apparent threats which is not ok
Look the kind of emotional response you get when you talk about Steve Jobs, Elon Musk or some other tech hero. It's off the scale.