Everyone finds some heartbreak somewhere.
You also seem to be asserting that, for example, I can't joke about my own cancer because it might offend my parents (who had a child with cancer... me).
Finally: I don't see that the joke is about Palin's kid... who she carries everywhere and mentions at every possible moment. It seems more at her.
Why isn't there a similar complaint at all the homosexual jokes, BDSM jokes, parapalegic jokes, "guy with helmet who drools" jokes, people with artifical limbs jokes, erectile disfunction jokes, etc.
Does Palin even watch Family Guy? Is she outraged over something she only saw because she heard she should be outraged?