After reading about the whole Maddow-Frum thing, I read through some of Frum's stuff on The Corner, and found him to be much better than your garden variety wingnut. He really did seem to be attempting civility, at least in the posts of his I read, and he seemed about as intellectually honest as a politically-minded person can be. So I tend to take him at his word that he really is unhappy with the general tone of our discourse, and God knows, there's plenty to be unhappy about. That being said,
1) You can't expect to go on someone's show and attack it and not expect a fight. Whatever his intentions, if he didn't want a fight, he should have chosen his words with more care. Since he's smart enough to know that, I can only assume he wanted a fight.
2) I don't watch, don't even own, a TV myself -- the only thing I know about these shows is when I watch what they post on the web. I haven't seen any of Maddow's work except a few interviews she did (which I liked), but I'm going to go out on a limb here and say probably Frum is right about the tone of her program. He has to be, because that's what viewers demand. Viewers want sarcasm, want anger, want to see their political foes belittled and laughed at. That's the nature of the beast, and complaining about it is rather like complaining about the politicians we, in our democracy, put in power: everyone does it, but in the end the only people to blame is ourselves. Which brings up ...
3) By far the worst, sarcastic, demeaning belittlers along these lines have been the people on Frum's own side. Limbaugh has made hundreds of millions over the years doing it, the radio dial is full of it, so are the TV screens, the op-ed pages: it's everywhere, and has been for years. Has Frum ever complained about it before, when the vitriol has come almost entirely from his side? I'm going to go out on a limb again here and say no, he hasn't.
4) Maddow didn't do the best job of handling the dispute. Pointing out that she isn't calling for anyone's murder or some such doesn't deal with Frum's main point.