Mind you, over on another topic where we debated the right to freedom of speech and expression, the right to offend was one area where a number of us agreed, provided it wasn't 'gratuitously offensive'. Now, for that, I'm afraid most of the best of the most offending comedians are brown bread: Bruce, Hicks, Allen, Pryor...
But parody, caricature or satire is not meant to be without offence to someone at some level. That's why it is what it is. If you want inoffensive comedians, you probably need to reincarnate Rod Hull and Emu.