Racism is subjective. Unless you out and out call someone the N word, then it's often difficult to know whether someone will be offended nowadays.
Someone on another forum discussing this used the term, coloured, which someone else said was racist. At one time it was the accepted term, now it's not PC. Years ago people of mixed race would refer to themselves as half caste, now that's not acceptable.
Many people call themselves black, some people find it offensive, some want to be afro carribean, african american etc... the list goes on.
I'm not saying he wasn't out of order, but unless someone is standing there using the words to hurt and offend it's hard to know nowadays. Sometimes it's ok to joke with people, or along with people, other times it's not appropriate.
One day, colour will be irrelavant, not in my lifetime I know, but I hope as time goes on the discussion dies out and people can just get on with being people. To quote Michael Jackson, "I'm not going to live my life being a colour" ( He sure took that one to an extreme!)