Arbitrary classification does not make a functional group. There is a distinct difference between a coordinated group and an abstract group that is the result of external parties adding people into named buckets for their own purposes.
Care to give some examples of what you consider to be coordinated groups, functional groups, and abstract groups?
I am assuming that your point is that prejudice is ok to some type of group but not other, but I am inferring that from your answer. Feel free to correct me.