They did IP ban him.
Frankly, I've never been fond of the way that being a mod is seen as some kind of status symbol. I used to be an admin (and before that, a mod) on a similar site for years. It's an unglorified job at best, one I do not wish to have again. It's not a popularity contest, even though everyone seems to make it out to be (and did back then too). Mods aren't the "popular" ones by far, they're the thankless, unsung heros operating mostly in the shadows, minus the "heros" part. I'm not going to lie, it burns you out after a while.
When you're a mod, you learn to appreciate the "user" role that much more. They have the freedom to have fun and be themselves, whereas with being a mod, you represent the site and the community. All those political viewpoints? Can't have 'em. Religious? Can't mention it. Controversial issues? Can't take sides. And for those that still want to be a mod after all this, remember this: mods don't make memes nearly as often as all the regulars on this site do, with good reason. They're busy doing their jobs, and are quite restricted in what they can post.
TL;DR: being a mod isn't nearly all it's cracked up to be. Chances are, if you go out of your way to try to become one, you're not fit for the job anyways.