He does this thing where he expresses a very strong opinion, which he then compartmentalizes into a single simple phrase, and he becomes unable to think of the topic at all beyond that simple phrase.
I remember having am argument with him about whether Columbus Day is racist, and he refused to try to expand on his thoughts further than "it's celebrating genocide" and assorted variations of that phrase. He could not properly address even a single point I brought up, and would instead try his hardest to find reasons to dismiss my arguments out of hand, personally attack me, and simply repeat variations of "it's celebrating genocide".
I saw him behaving similarly in a recent thread where he was talking about "america isn't the world police" and "america shouldn't own the seas", and he would again try to deflect all arguments by using those phrases and attempting to insult people.
I've yet to read through the thread that contains the post that got him banned, but it seems he was behaving similarly there too.
He very clearly has some sort of deranged hatred of the U.S. and he seems to have some kind of mental malfunction that renders him unable to exhibit any sort of critical-thinking.
This kind of behavior, while on its surface appearing not too bad, is awful for a forum. He's unwilling to discuss anything, he simply wants to state his opinion, and then he tries to talk down to anyone who disagrees with that opinions. He consistently derails and shits up entire threads with this behavior.
That said, I'm not a mod. Maybe their logic for banning him is completely unrelated to what I just said, but in any case his absence seems like a net positive.