I think saying it's a joke is a cop out. Yes, it's a joke. But just because it's a joke doesn't mean that it wasn't offensive. There are jokes that are lighthearted and funny, even if it's making fun of someone. There are jokes that are distasteful but can still be taken in good faith if the right person says with it the correct voice inflection and within the proper context.
Take the proper context, the proper voice, and the proper person away and that distasteful, yet funny joke, becomes incredibly offensive and unfunny. "Red Eye" failed to get even one of those correct. Given the jokes made in the OP, who said the jokes, and what the subject matter is, even I was angry over them and I'm not Canadian. To me it's blatantly obvious that these jokes were mean spirited. It just comes across as some bully making fun of some kid on the playground. This is why "Red Eye" fails so badly, it doesn't understand how to do comedy. What it calls a joke is just offensive. I get the feeling that a lot of conservatives, such as Ann Coulter, just don't understand comedy. The jokes themselves were just bad too. It'd take nothing short of a comedic genius to make those funny (seriously, calling making fun of the name "Leslie" was 4 year old humor), which Red Eye surely isn't.
It's what Sally said. Subject matter like this should only be approached by people who are very good at comedy, and that isn't Red Eye.