People have the right of free speech. With that said, comedians such as Daniel Tosh and Dane Cook like to use offending jokes in their stand-up acts. They have the right to try and shock their audience. That audience has a right to boo or laugh. It's all a matter of choices. We have the choice to not view these comedians and I think this is the most powerful form of feedback to them. Stop going to their shows or watching their programs. Loss in the wallet is a big motivator.
And just for the record, I find rape jokes distasteful and mean.