United handled this very poorly and they won't get my business anytime soon.  However, for Chinese to take offense to this just because the passenger was Asian and possibly Chinese is misguided and reflects a deeper insecurity that is prevalent among the population in China.  This cry of "racism" from some Chinese is a knee jerk reaction to their feelings of inferiority towards Western countries and America in particular.  The funny thing is that I've seen time and time again in China where "western" people were treated far better than native Chinese simply because of their skin color.