It's not hypocrisy at all! If a muslim said it, he probably wouldn't be joking. If an upper/middle class english guy says it, he probably is. This is in fact exactly the type of humour that should be encouraged. It makes people think about the real issue of stoning people to death, which is obviously bad, and just one of a whole bunch of things the muslim world needs to take responsibility for and put an end to. Now he can't actually say "I think muslims should probably stop stoning people to death" because that would be horribly rascist and insensitive to their "culture." This is actually calling muslims on THEIR hypocrisy, and that's why it's funny.