Most of those countries listed while they have multiple ethnicities, the police cannot tell one ethnicity from the other, readily, so I don't think it's a big factor (outside Brazil), so yeah, Egypt and Pakistan have ethnicities that hate each other, but the police don't filter for ethnicity and then deliver violence, they are just violent.
Also, police mistreatment is not only killings (which can be sometimes be justified and other times not) but also rights violations and other lesser violence. For example, you are extremely unlikely to be killed by Japanese police (they can bet perps will not have weapons) but once you get arrested, you have very few rights. Other places are rife with bribery and corruption (Mexico, Brazil). In Spain you might get the rubberhose treatment, and anecdotally, I know someone who got a very nice dog sicked on to them by the police in Germany (it looked like you were running away!).
I think the fact that you are familiar with stark racial divides has attenuated your sense for how perceptive hate can be. I know Irish who can tell an Irish Traveler from a non-Traveler in seconds, and accurately. Hate can be so easily fine-tuned.
Also, police mistreatment is not only killings (which can be sometimes be justified and other times not) but also rights violations and other lesser violence. For example, you are extremely unlikely to be killed by Japanese police (they can bet perps will not have weapons) but once you get arrested, you have very few rights. Other places are rife with bribery and corruption (Mexico, Brazil). In Spain you might get the rubberhose treatment, and anecdotally, I know someone who got a very nice dog sicked on to them by the police in Germany (it looked like you were running away!).