Nothing, if it were an isolated event. It's just that it's virtually ALWAYS a white guy being portrayed this way.
Try to imagine the ad I described with a befuddled wife sitting on the couch, and her 11-year old son, and her husband, condescending to her in like manner. Impossible. Never happen. The NOW picket line would be forming before the ad ended.
It wouldn't be funny. And we wouldn't like her, or him. That's the difference. We laugh at the situation with the hapless husband because it's IRONIC. IRONY is funny. That the man has to ask permission from the wife is what husbands joke about.