Heck, I’ll take a shot at this one.
First off: media whore is a pejorative term. Yes? Yes.
Second: Erick Erickson didn’t call Cindy Sheehan a whore. He did call her a media whore. We can hopefully pretty much stop pretending he didn’t mean to be insulting, right?
Third: if there’s something wrong with Cindy Sheehan using her access to media outlets to promote a particular commercial or ideological message, then there are a lot of people from all sides of the political spectrum who ought to be condemned.
What the Redstate folks are really saying is that they disapprove of her message; however, they’ve chosen to attack the person instead of what she’s saying. There’s a bit of subtext implying she shouldn’t have access to media outlets, but that’s a pretty profoundly unappetizing bit of subtext, so you won’t see it stated clearly. It’s always difficult to say “we don’t believe she should have a platform.”