Well one distinction I see is that there is a lot of misuse of the word
racism. Most of the time, what I see going on isn't
racism, but rather
prejudice. Racism implies, I am white, therefore I am superior. Personally I do not have racism. But I will confess, (and I think anyone who is honest with themselves would agree), that to some extent I am prejudiced. Prejudiced based on my experiences. How could I not be? When I meet a black person if they sound "white" for lack of a better descriptive word, I get an immedicate sense of "well he's one of us". But when I meet one who comes at me with a bunch of ghetto slang I am on my guard. In my use of the word prejudice I am not meaning blindly prejudiced, because I have experiences which I base my pre-formed opinions on, and while I may be wrong about most ghetto talking black people I would rather be safe than sorry, because I come from som BAD neigborhoods where you just don't trust anyone not of your kind. So yes there is a lot of prejudice, but I think actual racism is much rarer than one would think the way that word is so freely and incorrectly thrown around.
Prejudices are also often based in generalizations which are most often based in factual trends. It's not very PC, but it's a scientific fact that black children are physically more adept at an earlier age, on average, than white children. It's no accident that professional sports are dominated by African Americans. It is also true that Asians develop language skills on average quicker and more easily than white children or black children. It's no accident that they are known to be acidemically more adept. We caucasians are somewhere right in the middle. None of these tendencies is an absolute, and it's not even neccessarily such a large divide, but stereotypes, don't spring out of the imagination, and sterotypes are just another way to say prejudice. Prejudice has gotten a bad rap as a word, because it is often a negative thing, but if you touch an electric fence, five times and get shocked four times, you might, if your smart, have a prejudice (pre-judgement), about electric fences, and be very wary of touching them. Our prejudices can be negative and devisive, but they can also protect us.
In the case of the black teens beating the white boy, if they look into the
precedent, at hate crimes committed by whites, and find that white people who committed a similar crime, got similar treatment, then there is no "racism" (prejudice), but if the other crimes that set precedent indicate that whites were treated differently, then of course it's wrong. Unfortunately I think that white society, has so much guilt over slavery, that they fear calling this type of crime a hate crime and charging it with hate crime law, when clearly it's every bit as much a hate crime as it would be if it was five KKK members and a black boy.