Is it? This is the big question, as far as I can see. If my country has green people and blue people, and green people are overwhelmingly more likely to commit fraud, is it wrong to require additional fraud checks on the basis of being green?

Note that this isn't a conviction. It's accepted that the standard is not so exacting that no one innocent must be subject to investigation - that would be impossible under realistic circumstances. (Hell, even convictions don't meet that standard.)

On the other hand, I do accept the argument that you would have to be very, very cautious that you don't end up with a feedback loop if you did this - in other words, a system where you keep convicting green people because you investigate them, and the data therefore keep suggesting that green people have a greater propensity for crime, and so forth. That's undoubtedly happening in many countries, I'm sure.