I'm going to have to agree with that well-known <sarcasm>"arch-conservative"</sarcasm>, Bill O'Reilly. This is unfair, and when liberals do it, conservatives rightfully complain. So don't gloat and consider this fair payback. Denounce it equally. It's an inappropriate attempt to use media power to affect the election.
However, just because it's unfair, doesn't mean it shouldn't be allowed. It's simply wrong to limit free speech that way, and another example of why McCain-Feingold's "Campaign Reform" was a mistake.