My personal view for the Mods is that keep your biases aside and actually trace backward into the discussion and see who starts the fire.
Two wrongs do not a right make.
But two wrongs are not equal in culpability and effect either.
That said, banning is stupid. You lose talent. Simple. Everyone has something to contribute, if channelled properly. And as the old forum and most of us much-banned members have proven, banning does not stop a guy from coming back. And this time he will come back with 4 IDs as redundancies instead of one. And behave accordingly.
And you will forever by playing whack a mole.
Delete posts and have a word if you must. If the member persists, give him a time out from that thread for a reasonable length of time. Not permanently.
Just because he's said something wrong on one thread, on one topic, which might be a trigger for him, or might be in retaliation to someone else, does not mean he's all black and needs to be blocked from participating on other threads elsewhere. It will eventually be a large forum. Enough space for everyone and all interests.
Either way, we are a dying breed. Guys who still are on forums.
Don't thin the herd out further because someone gave you the online permission and means to do it with the click of a button.
Cheers, Doc