I basically subscribe to the Parker/Stone view that you can't declare a subject off-limits for humour without becoming hypocritical, because there's always going to be something that somebody else thinks shouldn't be joked about that you don't have a problem with.
That's not the same thing as saying that all jokes are funny. Jokes about rape can be funny, or they can be obnoxious, depending on the context (the scenario involving Tosh makes him sound like a bit of a jackass to me, but I really wouldn't make a firm statement). Pretty much anything can be funny. Our Dumb Century
features a number of hilarious jokes about genocide.
Another part of the Tosh controversy is whether rape jokes are overused, which...maybe? I really follow the world of standup comedy closely enough to have an opinion.