This Actually Explains A Lot
The other day when I saw Screech on Red Eye, I thought, "he's doing that bit unnecessarily hard. Maybe it's overcompensation by his nerves because he's on the TV."
But seeing the clip on Sadly, No! of Michelle Malkin reading the words of Amanda Marcotte (not all of them of course, just the ones quote mined for the limited purpose of mocking Marcotte's "insightfulness"), it all becomes clear.
A RWNJs natural response to anything is rage.
There's an episode of Law & Order: CI in which a mini-goomba is making a play to take over the "family" he serves by sucking up to the dying Don and killing the Don's son. Goren observes that the mini-goomba doesn't react to confrontation until he's gone through his internal rolodex of emotions to find the appropriate response. He's smart enough to know that rage isn't always an appropriate response. But it's his only natural response.
That's what I see in Screech and Malkin. They're "playing a role" on TV, and when they look inside themselves for what they imagine is the appropriate emotion, they find rage. Sure, they think they're just channeling a "liberal," as liberals are unhinged, unreasonable and angry. But does it always have to come out with such sneering vehemence? If that's the only thing they can find in themselves, yes.
Usually, deadpan is better, particularly since we liberals hold our own wacky beliefs with all sincerity. The beauty of speaking with utter sincerity is the contrast it gives patently insane words. The craziness should shine through on its own, obvious for all. That's one reason The Daily Show is funny; not much rage, lots of deadpan.
My guess is that if Malkin were to read Amanda's words with sincerity, the emotional impact wouldn't be what Malkin hears in her raging mind.