Animated sitcoms seem to have a niche that they aim for, the Simpsons is a family show, Futurama tends to the sci-fi fans we don't want to say we are, South Park is for the foul mouthed inner child in all of us. Family Guy has a stranger target.
Family Guy is the comedy equivalent to that piece of chocolate cake you nibble away at when you're supposed to be losing weight. You know it's wrong, but it's richer and more filling than anything else in your diet, that you can't help but cut yourself another piece.
It's the same with this, you know it's wrong to laugh about jokes about race, disability and other taboo subjects, so it shocks you to hear them, but when you see them in the nature of the show, they're either too surreal to accept as being true, like Hitler with his own TV show, or to show how unintentionally stupid and insensitive some characters are, like Peter's comments about his neighbour in a wheelchair who's better than him in pretty much every way, and it's because the writers find a way to talk about such taboo material in such an open way which exposes our dumb prejeduces, that adds a little shock to the humour because you never expect a show like this to be so upfront about it, and it's that shock that keeps you on the edge of your seat so you can try to catch the next one.
If any of what I've said puts you off watching it, then don't watch it, the show doesn't pull any punches, but if you're curious about how a baby can get away with saying he's "Cuckoo for Crack" or how you could get away with laughing to that and many other desktop-startup-worthy jokes and quotes, then go ahead and sound-proof the doors and windows so the neighbours won't complain from the fits of laughter when this arrives in the mail.