Jeph knows that the forums need to exist, but he hates what goes on in this one. Of course, when it gets a bit less horrible, he might be a little more relaxed about it (or not, some artists dislike any discussion of their work, preferring to let it stand for itself).
The forums do not "need" to exist. Jeph could be perfectly happy by taking a page out of Chris Hasting's practice and letting some overzealous fan create forums on their own hosting and leaving an "unofficial forums" link to it in place of his current one and forgetting about forums that discuss his comic forever (and save whatever bandwidth costs come out of it). Or completely ignore the existence of any given forums whatsoever and have no links to them, either.
Jeph
loves the shit that gets posted here, otherwise he would
do something about it other than post passive-aggressive remarks about how much he hates the people that talk about his work (or appointing someone that does it for him, which is unbelievably presumptuous of you). He isn't fooling anyone with his actual posts (they always come across as that not-really-funny deprecating sarcasm that hipsters like to use), so he might as well be honest
with himself and embrace what he has created.
Or basically, Put Up or Shut Up. Jeph is quite literally God as far as the forums go (he created every aspect of the content that goes into them, or provided the fuel for all other derived content, after all), so anything that happens is 100% his fault.
Welcome to The Problem of Evil: Webcomic Forum Edition.