Charles, we've had that discussion before. The answer to your question is: obscuring the fundamentally alienating nature of the socially engineered US society and capitalism in general. It would give another excuse for assorted liberals to say: if those people just stopped being bigots and racists, the system would work just fine.
I am not trying to deny the existence of deeply embedded racism in places like police departments or in some segments of the society. But let's not forger that racism is also a very useful feature for the ruling class, because it diverts attention from the malfunctioning of the system, and puts the blame on individuals.
Much of the hatred directed at people who are different (skin color, sexual orientation, religion, national origin, etc.) is rooted in the class nature of capitalist society. Eastern Europe is a good example. As long as class differences in those societies remained very low by capitalist standards, bigotry was also low. It does not mean it did not exist - but that it was not such a powerfule force as to drive people to start attacking each other. After the introduction of capitalist class divisions - we all see what happened: nationalism and bigotry running amok.
The bottom line is that we should focus on racism only when it is directly and unquestionably visible, such as in the police behavior or explicitly racist groups. But we should refrain from using racism as some people use Hitler - as an emotive label rather than a term that points to the root causes of the phenomenon.
>From what I've in the media, the two students in Colorado hated almost
everybody - they were not distinctively racist in the sense racism
manifests itself in the US - i.e. people having normal relationships with
people of their own ethnic groups, and hostile relationships with people of
different ethnic groups. This is much different from the behavior of those
two kids - who had hostile relationships with about everyone else.
Wojtek