Racism is quite easy to understand.
Racism is kind of like a hangover from our tribal days, it's an ingrained fear of the 'other' which exists in all of us subconsciously as a safety mechanism. In tribal society, if you were in tribe A and you saw tribe B who looked a little different coming over the hill... well, it payed to be on your guard in that situation. They may be coming over to play tiddly-winks or they may be coming to start a war. So that whole automatic thing where your psychological defenses go up when you see people who look different approach... that's a perfectly natural, normal thing, and in this sense, everyone is a little bit racist. It's nothing to be ashamed of. It's nothing to be particularly proud of, either. It just is what it is. As soon as you realise that that Tribe B just wants to play croquet, or that the guy at the back of the bus with the different skin colour is really quite a nice old chap, then the guard drops somewhat and social interaction returns to normal.
Most other data can be ignored completely. More blacks being in prison says more about the way black people have been treated and had their societies shaped by invading forces and racist policies throughout history, than it does about a black person's "genetic" ability to stay out of prison. Jews and Asians scoring higher on the IQ test than whites tells you more about IQ tests and the structure of learning and cultural imperatives in Jewish/Asian societies than it does about Jews and Asians on a racial/genetic level. Social factors are what causes these differences, not racial factors. Sure, the social factors may be race-determined (people, listening to their inner subconscious fear thing mentioned earlier, may not want to mix with the "other" race, so they draw up rules to make it so that the other race doesn't get their bit of the pie) but it's the social rule that determins the racial rule, not the other way around. Genetic differences between humans are so muddled that "race" alone is genuinely not a useful factor for determining anything at all about the way humans think or act. And this, above everything else, is why making race-based policies is stupid. "Race" in the traditional sense doesn't really exist in any clearly defined way, on a pure biological, scientific level, apart from superficial things like skin colour and hair texture (and even that's not 100%). Racism may or may not be morally wrong depending on your morals, but it is definitely scientifically wrong. That's why the Nazi scientists never actually found anything out in all their years of study. Their "scientific discoveries" were thrown in the dustbin as soon as the Allies took over, not because they were immoral but because they were incorrect.
For more information about race and genetics: http://raceandgenomics.ssrc.org/Lewontin/