I wrote for Maher and PI for just over a year, and, yes, the guy does fancy himself as a take-no-prisoners straight-shooter. He also believes himself to be an intellectual. But his politics are a soupy blend of libertarian posturing and servility to the imperial state. The views he expresses on his show are genuine. It's no act.
You can chart the rise of rightwing comedy from when P.J. O'Rourke took over the National Lampoon in 1978. He turned the magazine to the right and bragged about his "screw you" humor. He ran unbelievably racist cartoons (which would have been at home in any Klan paper) and turned the Lampoon guns away from corporate, military, religious and elite targets, and set them on blacks, Asians, the poor, gays, etc. -- what senior Lampoon editor Sean Kelly (whose son Chris is the head writer at PI) called "Cossack humor." A couple of years later the Dartmouth Review was founded and went this route, and there was of course the American Spectator (nee The Alternative), which ran a lot of O'Rourke's material.
You're right, Doug: the whole politically incorrect concept has been a cover for "conventional bigotry."
DP