I saw plenty of fights in High School, and it was pretty common to hear racial slurs during the fight. But those fights didn't start because a white guy wanted to beat up a black guy because of his race, or vice versa. It just sort of came with the package... you throw punches and hurl insults. If someone is a certain race, that's an easy insult for the weak-minded.
They should be put away for a very long time. They don't belong in civilized society. But focusing on the racial slurs and the races of the kids involved implies that this is somehow a greater crime because the victim was a particular race.
Anyway, I'm not gonna soapbox this one to death. Suffice it to say I think they should be severely punished for what they've done, regardless of why they did it.