Christ, if I were fined every time I made a self-depreciating 'retard' joke, the resultant money produced would pay off the US national debt... with enough left over to buy a brand new cuppy helmet.
Anyway...
As we grow closer and closer to the generations who have gown up under the 4chan umbrella, so will more of these kinds of things escape. Obama knows that he has to be excruciatingly careful with his speech now, but he is a mostly normal man, and things will slip through now and then.
In a way that's a bit of a shame. I rather miss the days when men carried their predjudices on their sleeves, because let me tell you, it's not that they've been overcome, or that we become all that much more open-minded (though we have made some tangible improvement, Obama symbolizing that in an impressive way), just that people know to keep their fool traps shut in public, which only masks the issue and leaves us with cardboard cutouts instead of leaders.