Bob Hope hosted the Oscars 19 times, starting before it was broadcast on television. He made fun of entire groups of people, as well as specific ones, and even alluded to the Nuremberg trials (Judgment at Santa Monica) in one of his opening monologues. No one punched or slapped anyone, however controversial his joke was.
http://www.youtube.com/watch?v=iOtp4dli7-4, starting at 2:01, first televised Oscars show’s Bob Hope monologue
http://www.youtube.com/watch?v=cRSAhrqpTBI, starting at 6:54, introduction of him and his first joke for several shows and then his 1975 monologue which had a moment that gave the audience pause.
All the hosts have made fun of specific people and Hollywood in general. Johnny Carson, Steve Martin, Whoopi, Billy Crystal, - all of them. Being the butt of an awards show joke is a feature of belonging to the Hollyweirdo crowd.