Your counter assumes that counterfactually they would be arrested at the same rates if they were doing the same actions. If they are not in fact arrested at the same rates even if they are doing the same actions, the counter doesn't go through.Using arrest rates only works if we ignore differential application of the law itself (and as my philosophy of law, and logic, classes get to learn, empirical evidence fully shows that the law is not applied equally across demographics 🤷🏼‍♂️)