Despite what much of the Internet thinks to the contrary, "just kidding" is not an automatic out when you express a controversial or offensive opinion, even if it really is supposed to be a joke.
Saying something is a joke doesn't make the original statement suddenly not exist; in fact, in the case of offensive "jokes," it makes matters even worse, because it means you as a person are low enough to try to pull humor out of putting down other people.
Joystiq's writers and editors should be ashamed of themselves for letting this article get through. It's incredibly unprofessional, and honestly, if I were in charge of any of the ad firms they use, I'd pull my ads from their site, because I wouldn't want to have that kind of opinion associated with anything I'm selling, even if it is a joke.
"Can't shake the devil's hand then say you're only kidding."
-They Might Be Giants, "Your Racist Friend"