With that post, he makes it impossible not to lynch him. We simply can't afford to let him live and then have him winning this game as mafia. Even if I would be 99,99 % sure that it's one of the other guys, I still would lynch Pizza. A 0,01 % chance that he wins this game as mafia after that post and all his claims of being mafia is a risk I, for one, wouldn't want to take.

If he's mafia and we let him live after that post and all those times he claimed scum, we'll all be the GR's laughingstock for years. No, can't have that. Even if GH would now make a post to say it's 'khaan or JHT, then we still need to lynch Pizza. Even if the chance he's mafia would be only 0,00000000000000000000000000001 %, we can't have it. No. Even if he would be guaranteed innocent, we can't have it. Imagine the host saying, "oops, mistake, I meant 'khaan, not Pizza". No, no, no.