The funniest thing I ever saw on the Oscars was when Jim Carrey went up to present an award, and then started re-enacting scenes from Midnight Cowboy with Woody and Buzzlightyear dolls.
I stayed up late that night and watched that as it was broadcast live, hilarious. But, I wanted to tape it later, and they cut it right down on all the repeats, really annoying, I think because he went out on a limb with it, like the best comedians do, nothing offensive, just y'know, surreal, and that was what made it very funny.
So, it's not just them wanting no-one offended in any kind of political sense, they also don't want anyone showing *too* much creativity, ie they want someone up there being safe and boring, exactly what Eddie Murphy does best these days in his movies.