>Just as, for example, if a business decided (if it was legal) to only allow people of a certain race to enter, I would like to think that most members of that race would be disgusted enough to boycott that business and the business will rightly fail.

We literally have federal laws outlawing this because it was, in fact, a selling point to exclude other races. Are you unaware of the history, or just hoping that racism has successfully been ended in the United States?