And what would that reason be?
I'm not sure to be honest. I just checked out his site for the first time and don't see many blog posts or what not, so it could be that. But I think it's equally plausible that imbalanced moderation has led to an online culture where Republicans go to other sites to discuss politics. But it'd be hard to pin down with more certainty without access to data.
edit: Blader brought up an interesting point that the more relevant comparison might be referrals to Trump's twitter, which I feel is probably right. I'm not claiming his site is worth visiting or citing (if anything it seems rather empty after having visited it), but I think the broader point that the viewpoints of republicans are unwelcome (specifically by moderators) on NeoGAF can still contribute to a lopsided representation of society at large.