The idea that America's history with racism somehow forecloses the possibility that Khan will be accepted is ludicrous. I would think this retort so simple and obvious that it wouldn't have to be stated, but here it goes: The vast majority of historical atrocities and malevolence has been directed towards blacks, yet many of the most popular American fighters today are black. If that can be overcome despite this "endemic" racism, then I don't see why Khan could not make an impact, as well. You don't have love a race, want their men to marry your daughter, give them substantively equal treatment, etc. to root for them in a fight. Does the fact that he's a Muslim of Pakistani origin hinder him a bit? Perhaps, but not nearly to the extent being alleged.
I'd say the fact that Prince Naseem Hamed was able to become a mega star here (even as a villain) says everything you need to know about the idea of there being racism clouding their ability to judge a fighter. For ****s sake a fight between a Pinoy and a Brit did almost 1 MILLION PPV buys in the states! Were they buying it because Humberto Soto was on the undercard?