Probably don't come on forums anymore, there are still forums sections moderated. Halo: Reach forums has moderators regularly posting there. It's not like they signed a contract or something, they don't have to come online, there's been less trolling on
here since they left to be honest. As for COD section, what do you expect, the majority of the COD community are the idiots of the world.
They probably can't moderate because the forum is too messed up for them to be able to. After a few "Ooops you've found a glitch in our system" pages after trying to lock and ban someone I think I'd just give up aswell.