Correct, but in reality, the police doesn't go do some random control in the streets of some randomly selected rural area. They will target locations where they are likely to find drug dealers, target behaviors that are likely to be drug dealers, etc. So the numbers aren't those from your theoretical example.

Though in reality, I mostly hear about racial profiling in France in the context of looking for illegal immigrants where the odds are even more skewed against a population than your example.

The moral argument is orthogonal from the efficiency argument, and I totally agree with the frustration generated by misguided checks (and am reminded of those every time I take a plane).