Culture fit is a very loosey goosey term, one that is easy to abuse. What you want are people who fit well into a team. You want them to be able to do their job, and you want their participation to raise everybody else's performance, too. That's not so much about "culture" as we commonly think about it, as it is about working style. That's probably not something the average manager can grasp, so "culture fit" becomes much more subjective and useless, and I am not surprised that it would also become racist.