And yet, many businesses did so in the racist South and in South Africa.
Why would that be an "and yet"? If a society at large is racist, the businesses that fail and the businesses that thrive alike will be lead (to a large part) by racists who make racist decisions whether or not those make any business sense. Even if some of the businesses that fail fail in part because of unwise racist decisions, that won't make the situation go away when the startups that perpetually replenish the pool are, too, overwhelmingly lead by racists.
Conceivably, even if the society at large is not dominated by overt racists, a business class making racist decisions can perpetuate itself. If 80% of the successful businesses are overtly making racist decisions, someone trying to emulate the rich and successful (i.e. most founders of start-ups) will come to the conclusion that doing so is part of the formula, that those racist decisions make business sense even when they don't. If 90% of the start-ups do come to that conclusion (definitely not outside the realm of possibility), even if those racist decisions are counterproductive to the degree that refraining from making them makes a business twice as likely to survive and thrive long-term, the next generation down the pipe will again end up emulating a business class where 80% make racist decisions.