Have you reported it? The mods don’t guarantee that they’ve examined every thread in their forum. The best and quickest way to draw attention to a problematic thread or post is to report it.
Are posters attacking each other? If not, it doesn’t need to be in the pit though it may flourish there.
You’re going to need to posts some specific posts or comments that you think are pit worthy. I strolled through that thread, and don’t see anything that screams “PIT” to me.
I didn’t see anything even remotely Pit-like in that thread, aside from a few attempts at making up naughty words on a couple peoples’ parts. “Cuckservative” and “Fuckstick” being the most prominent.
Then again, yeah, maybe they’re holding back because they don’t want to sully the august sanctity of IMHO.