I don't really have anything against the guy. He's entitled to his viewpoint as anyone else - sometimes I might agree, sometimes not - just as it might be with anyone here or I might know in real life. I do think he has a point in that, even if it might be well-intentioned, some of the heavy-handed, sanctimonious brow-beating we see from some on the left might put people off.
I daresay that a lot of what goes on is that, people are justifiably angry and resentful of what we know has happened in our history - gross injustices, abuses of power, exploitation, intolerance, bigotry. I'd like to think that the worst is long behind us and that overall, our society has gotten at least somewhat more enlightened - more or less. We still have a long way to go, but we've made some progress over the centuries. But there's still this underlying bitterness and resentment which doesn't really go away that easy, and oftentimes it's passed from generation to generation. Not everyone feels the same way about it; it seems to be different depending on one's perceptions and background.
So, regarding what Maher touches upon, it seems part of a general process involving society's attempt to resolve what has happened in this country - historically, socially, culturally, politically - but it's not as cut-and-dried as some people would like it to be. And frankly, what Maher is really pointing out here is that, overall, at least when looking at politicians, government officials, and others in positions of influence and authority, they seem to be incredibly poor problem-solvers. Even if people agree as to what the problem is, they can't seem to come up with any workable solutions.