Getting the right punishment is much more complex than it seems. For example it has to be punishment that is seen as punishment by those receiving it. For all we know it might be seen as some kind of perverse badge of honour. We assume these racists will be affected by the punishment - you've got to be careful when assuming that everyone thinks the same way. Other problems are
> punishing people that have nothing to do with the problem
> just moving the problem somewhere else
> if you punish people that believe in what they are saying/doing then you could be simply reinforcing those beliefs
> how does the punishment change people's mind about their behaviour
If the punishment doesn't change someone's attitude then it is not much more than making us feel better. There is certainly some merit in that, particularly to those directly affected, but it doesn't do much to prevent repeat problems later on.
We all apply our own value systems to such situations and assume that punishment we would not want, they would not want either. This is not necessarily true. Find out what they don't want to happen to them, and work out what would actually stop this happening again.