Oh, he is, believe me. But the thing is, he's a clever ass; he know what he can and can't say, and deliberately pushes the boundaries of decency and taste just to get a reaction. He means very little, if any, of what he says.
The thing is, I personally don't think accepting stereotypes - be they ethnical, racial, etc. - is that easy or will make them magically "go away". People will always say hurtful things for whatever reasons. Taking it as a joke and sweeping it under the proverbial carpet doesn't change the fact that they're often done to be cruel and offensive. As far as I'm concerned, there's a line in comedy you don't cross, and I wouldn't blame people for feeling uneasy around those kind of jokes.
But to get back to the original point, I just think the whole "Irish people talk like leprechauns" schtick makes them come across as ignorant. If you're going to make a joke about being Irish, at least come up with something more original.
But that's the thing! It's like bullying. As long as people feel butthurt about stereotypes, people are gonna keep making jokes. Why do you think the internet's all immersed in activism through Mohammed jokes? Because Islam just doesn't accept them. And comedy can allow for ANYTHING. Comedy is that one threshold that people can be free to say whatever they want. Look at South Park. They make fun on what's current, and what sets people's minds on fire. And that's what makes it good. The fact that it can make Scientologists and their shitty money scam religion so damn nervous. You can make fun of catholicism and christianity all you want nowadays. But do you see tons upon tons of jokes being made about that? No. That's because nobody cares anymore. It's commonplace. They don't feel offended with every single thing, and people have stopped looking for reactions. But comedy, you just can't stop comedy. Comedy is, among other marvellous things, the art of being hurtful. The art of offending with humor. Because as offensive things happen, people are gonna get riled up, and other people are just gonna be looking for reactions from them, just "for the lulz".
Thing is, stereotypes exist and they'll always, always exist. It's better to make fun of them ourselves and live with them, than be offended by every single one of them. I make fun of my stereotypes daily, along with tons of my friends from different countries and ethnicities. Talking crap about each other is a friendly way to show we're close. Being offended about small stuff just makes you look like a stuck-up [Bumpity-Boom!].
Now shut up and give me your lucky charms. I wanna wish for a HUUUUGE barrel of sardines I can eat in my dirty old VW.