Here's the thing about The Simpsons: This family really cares about each other. Homer does dumb things, but in the end, his love for his family is apparent - and whenver he gets a guilty conscience, it's Marge he's thinkig of. Even Marge's sisters, who hate Homer, respect the bond that Marge and Homer have. Sure, Bart and Lisa can't stand each other, but if someone else is mean to one of them, what happens? They come right to the other's defense. No one is perfect, but if you have a true love for your family, that's not a bad place to start.
(And I agree completely - it's not MEANT to be a kids show. It's hysterically funny, but you need to have a lot of real-world knowledge gained through real-life experience to get most of the humor.)