They haven't said anything aside from a generalized "We did an AMA with 8chan sorry" because of course they're not going to claim any specific post from that mess, but considering how everything went down during the AMA and THQ's non reaction during the AMA it's pretty obvious all those posts were from actual THQ employees.
I'm with you on everything but that last part, I'm not familiar with 8chan but I'm assuming it's like 4chan and I'm operating off of that. I don't see any kind of trip code or anything next to his name, so I don't agree that it's pretty obviously THQ saying that. While admittedly that would make the story "juicier" for drama if they were, I don't see how that couldn't be some anon just shitposting and impersonating them.
They deserve to get lambasted over deciding to host there though, guy should lose his job, but I don't think the homophobic comments that were made can be linked back to them with 100% certainty.