Gaffigan is a subversive voice, for the reason others consider him so middle of the road: He’s able to talk to everybody, and that puts him in a position to affect more societal change than the trio of “on edge” comedians mentioned above.
Comics “on the edge” tend to have edge or fringe followings. Stanhope is fantastic, but he’s a niche performer. Cross may be offensively poignant, but he’s preaching to the choir. Same goes for Garofalo; as much as she is able to rally the left, she’s not changing any Republican minds.
Now, take Gaffigan: he’s less vitriolic than the aforementioned comics, but he’s certainly found a way to criticize people to their faces—and because of his wide appeal, he’s been able to accomplish this on a larger scale.
In the comments there, Gaffigan's inside voice is brought up by someone named Roped:
what you’re missing here is Gaffigan’s strange voice that talks back to his jokes from the perspective of a confused (possibly female) audience member. This tic makes him more subversive than any of the other comics you’ve mentioned because he is able to play with our responses by responding to this voice. Through this he goes beyond simply stating what he thinks in the way you’ve mentioned. Like, he’s not just going “I HATE OBESITY AND CRITICIZE IT” but he can display both sides of the conversation. It is wizardry.
Good point that. I've heard Gaffigan refer to it as his "inside voice." But to me, it always seemed more of an "outside voice" — him acting out the thoughts of a conservative, easily offended, female audience member.
And that's the beauty of it. It shows he's completely aware of how he's being perceived, which lets him get away with saying on-the-edge stuff. It's like a bumper that minimizes any damage. Plus, it also shows the silliness of those thin-skinned soccer mom types.
And one more thing worth mentioning on the topic: Sometimes Gaffigan is just outright subversive. Take this chunk he does on religion where he tackles the virgin birth, pearly gates, people who talk a lot about Jesus, the burning bush, etc.
I don't think the Jesus stuff is why he's so popular. To keep up his mainstream appeal, this kinda thing needs to be sandwiched between bits on bowling and Hot Pockets. But sometimes it takes some sugar (or bacon) to make a pill go down.