Well for a start, it's a debate. And second, there's no point. When someone comes up with a good point that counters yours, you just say "I'm just kidding, don't take it literally". Either join in and counter those posts with your own, or don't bother posting.
I want you to read his post.

You are just pissed because you said(in more than a single post) that he accomplished nothing, and I proved you wrong.
Well, deal with it.
He said he proved me wrong because I said Seph accomplished nothing and he showed me proof that he did in fact accomplish things. Isn't what I said to this basically a counter to this? I mean, yes I said Sephiroth accomplished nothing, but I was exaggerating. If you wanted me to break it down for you then fine. Sephiroth accomplished little compared to Kuja. But you know what? I'm just going to exaggerate and use sarcasm everywhere now, and you guys are going to take it so seriously too.

Sephiroth, maannn, this guy...definately not overrated. Man, we need to showcase this guy more because obviously, he's not being showcased enough. We need to put this guy on Kingdom Hearts III and make him like...the most powerful guy in the game because we so didn't do that enough in I and II.