Theymos limits what he can do as far as deleting posts and banning spammers.
AFAIK hilariousandco has stated a few times he has very little contact with theymos, and I doubt there's many restrictions in place. After all it's up to the individual moderator on how they deal with something. It's probably a lack of time, and not enough reports. As well, as partly giving up fighting the masses of spammers.
You could be right, of course. Obviously I'm not privy to any communication between Theymos and any of the mods, and I don't even have anything to back up what I wrote--but I swear I recall either Hilariousandco or Lauda stating something to the effect that Theymos doesn't want all these shitposters banned.
I would agree that there's probably some throwing in of the towel on Hilariousandco's part and that's understandable. It's harder to find good posts on Bitcoin Discussion and Economics than it is to find shitposts. I'm also aware that as soon as these jokers get a neg, get banned, or get so much as a handful of posts deleted, the noise they make is deafening. They'll spam your PM box to no end, and they'll make threads complaining about their situation with every excuse and blame-deflection known to man. It gets very tiring very fast, and I'm sure it's worse when you're a moderator.