First, I'm not a moron. Of course I realize it's a joke. It's the attitude it perpetuates, witnessed by some of the replies, that I find offensive. You can say it's just humor, all in good fun, but think about it. This is how it starts. It's a mind set, an attitude. Saying it's a joke doesn't mean it's acceptable. What you think and what you say has consequences.
Second, it always amuses me that people like you can very freely name call someone you don't even know over the safety of the keyboard. I'm pretty sure you wouldn't be so free with name-calling if we met face to face. I could stoop to your level and insert a few names to call you, but I don't know you, and, well... then I'd be down to your level.