It's needlessly demeaning. I mean, sure, I could get behind gloating, but I'd do it in a classy way, you know, stroking a goatee and a kitten.
Okay, what I'm trying to say here is I don't see a purpose behind it except for going "FUCK YEAH, BITCHSLAPPED!" at someone who can't defend. And that I see a user avatar as a rather personal thing, an extension of one's forum personality, and it's rude to mess with that. So they should have behaved so they don't get permabanned and they won't have that problem, you say? Sure, I suppose there's some truth in that. But adding insult to injury is childish.
That, and I haven't been permabanned and still have a problem with it...
Rant over.