Surely that's very draconian, though? We'd effectively be getting into territory where people taking offence at comedic material results in criminal prosecutions. Do we do the same for fictional TV shows? Because if not then comedians can, of course, then claim they're effectively playing a persona during their shows; Boyle's material is ridiculously offensive, at times, but for the most part he's a fairly charitable left-wing liberal.
I also worry it wouldn't really reflect wider society as a whole, and would be attempts at enforcing changes people don't particularly desire. The guy in this case is quite clearly an absolute cock, and no one I really know repeatedly uses phrases like 'Gas the Jews' relentlessly in some attempt at humour, because it's quite clearly not funny...but at the same time a lot of people make off-colour jokes. It's always happened, and it will continue to happen. And for the most part people tend not to be particularly annoyed or offended. Attempts to restrict that strike me as wholly unenforceable, and an attempt to create a society which doesn't really exist at all.
And I get why people would argue for this. Because a lot of people will often hide behind off-colour humour to disguise off-colour views, and a lot of people will play the 'PC gone mad' card when they're quite blatantly being discriminatory cnuts. I absolutely agree there should be criminal prosecutions for people who incite hatred - racial or otherwise - and for people who harass others. While I support freedom of speech, it's necessary to have certain limits in place in order to recognise that it's not okay to say - or do - certain things. But I'm not sure general Holocaust jokes or 9/11 jokes should be worthy of criminal prosecution. That strikes me as too far. And something that a less than benevolent government - i.e. most of them - could distort to their advantage.