It has to do with incentives and identification which ends with action. If I am in a park full of black people I will be less safe than a park full of white people. This is because my statistical chance of being mugged and killed is higher. This is not theory. This is fact. I live in Africa. If I am not careful I die.
I only freely associate with black people I have verified to be trustworthy. I cannot give everyone the benefit of the doubt because then I would not be able to speak to you today.
Don't trust verify.