I don't think this has been aired more because Jade Goody's racism is more horrifying than some child from an ethnic minority being killed. I think it's because it was being broadcoast ad infinitum in the name of entertainment. Because C4 edited it to maximise the effect of the bullying - whether it was racist or not (as I've said before, I don't care what hook you hang bullying on, it's devastating for the victim).
Perhaps one positive to come from this will be for people to look at their own attitudes towards other cultures and just maybe realise that, to one degree or other, we are all a little racist. It's part of the human condition. We group together with those similar to ourselves - which automatically means that we, subconsciously perhaps, move away from those who are different. It absolutely doesn't excuse the sort of behaviour displayed on CBB, but it might make some of us fight against our basic instincts (as in a survival instinct developed over thousands of years, but probably not so essential these days) and make us more inclusive.