-1 Stupid.
Being "racist" doesn't mean you're a white supremacist necessarily, it just means you treat people differently based on their race, and that you have certain assumptions about races.
It's a very common assumption in America today that blacks and hispanics are stupid and prone to joining gangs, and that Asians are smart and successful. So anyone operating under those assumptions is naturally going to treat black suspects poorly, and Asian suspects well. Of course, like many stereotypes, the statistics kinda back up these assumptions, but that's the problem with racism (or any generalization): just because a group of people exhibits certain behavior on average doesn't mean every individual in that group conforms to it. Some poor smart black kid in the ghetto who wants to go to college and study CS can be easily screwed over (by the cops, the schools, etc.) because he lives around a bunch of dumb thugs.
The woeful underperformance of AAs is because of historical inertia and ongoing racism that comes from it (such as people like you who make generalizations, and then everyone in that group is forever screwed because they can't overcome these generalizations). African immigrants don't have the same historical problems that AAs have; they leapfrog over those problems.
Think about it: suppose you can either be born a dumb white boy in a middle-class family, or a dumb black boy in a ghetto. Which lifetime is going to be better? As a dumb black boy, you'll probably end up joining a gang or getting involved in some other criminal pursuit because of your peers in that area, the lack of opportunities, etc. As a dumb white boy, you'll still go to a pretty decent school, get a diploma, your dad will probably help you find a decent job, etc. I knew a guy in high school who wasn't all that bright (he wasn't stupid really, but he wasn't scholastically smart, and got put into the lower-level classes for non-college-bound kids). His dad was really smart and an engineer, and set up a business for them to work on together, so when this guy graduated high school, he just continued the business (internet sales) and made really good money and bought himself a really nice upper-middle-class house; he never went to college or had to work in some shit job like someone else with his educational background. Some poor black kid would never have had an opportunity like that.