He hasn't done standup in forever, but Larry David's whole thing is being a lolcow who looks at all of the normal social shit you're just supposed to do and says 'nah, I'm not doing that,' and then everything breaks, like a modern day Bartleby the Scrivener, he's just a self-aware one who harnessed it into a career. He is George Costanza.
If we're talking about lolcow comedians who also suck at comedy, though, Jim Norton. It's possible he's done something intentionally funny, once, maybe, but life's too short to wade through all of the shit to try to find it. He just reads as incredibly dumb. He's somehow stupider than the people he makes fun of, but he's dumb enough to think he's owning them. And while lots of comedians channel their hatred of women into their comedy, his brand of seething woman-hate is conspicuously that he's in denial about being gay and he's angry that women don't have cocks. He's hiding in a glass closet with his male 'wife,' coping by calling the tranny jizz he craves 'feminine essence.' Everyone can see you in there, dude, you're not hiding anything from anyone, you can just come out.