I'm not against changing avatars per say for reasons stated above (i.e. you broke the rules so you deserve it; you won't notice it unless the bans are recent or you go through the archives, etc), but I think the actual image is really, really crass. I mean, am I supposed to find a clip showing a kid in a hospital bed punched in the face, twice no less, amusing?
Also guys, whether or not you care about the banned person's feelings over having their avatar changed is really irrelevant here. Sure, who cares, they're banned and they probably deserve it... But I just don't think that the .gif is really appropriate for use in the, threads especially by the mods who would usually give out warnings for such content.
See, what you did just now is known as "necroing." That's when you revive a thread that's been dead pretty darn long. It's considered uncouth.