Given, Rape is a nasty concept, but honestly it was mere humor. Besides, people have some pretty bad concepts in mind all the time anyway. Ever considered the connotations of "Ya mum" or "That's gay" or "Go to hell"?
They're all commonly used phrases, but nobody makes a big deal out of them because they know that it's only joking. So, really, if you think about it this way it's not the people who make the statement who have the problem, it's the people who have a problem with the statement that have a problem, seeing as how society so openly accepts the statement.
Just adding some rational logic to the situation. I may not know, you may have some horrid history with rape or something, but honestly if you have a problem with it then why feel obliged to leave a comment at all?
And yes, I'm a hypocrite, but this is for educational purpose.
Before you get angry contemplate carefully what I've said, and re-read your own statement so you remember to put "is" between "fuck" and "wrong" next time.