No one is blaming O'Reilly or Goldberg directly for the killings that resulted. But there is at least some level of culpability here that they need to face responsibly.
That means dealing with the matter forthrightly: Reporting the whole facts of the matter (particularly that Adkisson was clearly inspired by their own incessant scapegoating of liberals, often with violent language along the lines of "Screw them") and making clear that in no way did they ever intend these words to be taken as a call to violent action.
Not that they ever will, of course. These guys are big battleships, dontcha know. Why be bothered with such little spitballs as basic decency and integrity?
I won't defend anyone leaving hateful comments at Goldberg's site but that's a far cry from someone being whipped into a frenzy to the point that they go out and shoot up a church full of innocent people. He's playing the victim over what some anonymous commenters wrote at his blog and he says that the Fox viewers would never do anything like that. Hey Bernie, go take a trip over to Freeperville if you think conservatives don't leave hateful comments on the Internet. Also unless you're trying to encourage more of them to do the same thing, don't go calling them "sewer rats".