1. When you're in a foreign country, nothing breaks the ice better than making fun of the indigenous culture. The people will instantly warm to you and recognise just how ridiculous their way of life is compared to yours.
2. Other cultures are incapable of solving their own problems, so it's only natural for an American with no prior knowledge of the country or its customs to do it for them. He may offend them along the way, but that's their fault for being a different nationality.
3. British people are either upper-class villains or upper-class stooges. As for Australians, they're just a bunch of jungle-dwelling criminals who can't be trusted. What do you expect from a nation of convicts?
4. Watching someone being raped is always funny, especially by an animal. If it's the bad guy it's even funnier because it's humiliating as well as traumatic. Besides, he's probably a closet case so he might even enjoy it.
5. Everyone loves a clown, so there's nothing embarrassing or annoying about an idiot man-child shouting repetitive catchphrases and pulling stupid faces - especially when his salary takes up approximately a third of the film's budget... Now that's what I call comic genius.