The bullying that is based on racism has some significant differences from bullying based on picking on a victim at random. That doesn't make it worse or better, but those differences are significant, they link it into things that happen in the outside world - political movements, headlines in the crap tabloids, harassment on the streets, race riots...

Intectious diseases aren't necessarily more unpleasant or life-threatening for the sufferers than physical accidents - but because they are infectious they demand a different kind of public response.