Who's the meanest person on createdebate
Meanest... that I've come across? Probably Garry or Assface. In my experience they don't really give a fuck about your feelings/go out of their way to hurt your feelings when debating. But I can only say these two are mean because I respect their opinions as cognitive debaters. There are plenty of other assholes and jackasses on this site, but most are so shamefully stupid and transparent it would never occur to you to be offended by anything they say because you're so busy laughing your ass off. I take Garry and Assface's opinions a bit more seriously than all that, which is why I can say thems some mean sons a bitches.
Also, not necessarily a bad thing. It discourages the odd person from wanting to debate with them, and they're probably not going to win any popularity contests anytime soon, but being blunt and up front is a perfectly valid way to debate.