For example, according to actual data I've seen, poor people really are disproportionately likely to a) have missed payments before, b) not repay your loan, and c) belong to certain ethnic groups. Some people may fit into one of these categories and not the others, but the correlation exists, so you can't clamp down on one without also measurably reducing the others unless you go out of your way to do so.

(Don't know who's downvoting, but I'm just stating pretty well-known facts. Don't take this to indicate approval — I'm just saying that, statistically, some groups do get the short end of the stick. What you do with this information is a different question entirely.)