Current distributions of property, wealth, access to services, etc. are all rooted in discriminatory laws and policies of the (not always distant) past. Which creates a risk that blindly pointing an algorithm at these data sets will result in an algorithm which assumes these are the expected/natural distributions and will optimize to perpetuate them, essentially becoming an algorithmic implementation of the prior discriminatory laws and policies.

Thus, unless the goal is to perpetuate the effects of discrimination, algorithms need to be carefully set up and trained to understand that "this isn't how things are supposed to be".