In 2008 they'd just use retard. It wasn't even slightly controversial of a word at that point, just like disabled isn't really now (since that differently abled nonsense euphemism failed to take off).
I think I remember seeing Hannah Montana in a commercial before then saying not to use the word, but it was still pretty common place in 07, just on it's way out.
I laughed at the comic, but I'm pretty sure likening 'very dumb/bad' to 'disability' is pretty controversial, even if the word disabled isn't, necessarily controversial on its own.