People getting carried away with the victimization story.
I get that most of the posters here, who are probably white, look at this as a good opportunity to tilt the racism story on it's head and pretend like it's the world's fault for overreacting as opposed to racism being what it is. Yes, this isn't the worst case of racism we have seen - if we give him the benefit of the doubt, he very well could have not meant any harm by it.
Having said that, there's two things to consider here:-
1) Racism is very real. Racism in Europe is very real, and racism in football is very real. Within this context , you cannot be making a loose comment like identifying a person by his skin color, in the capacity one of the OFFICIALS in the game. When there is such an immense effort to battle racism, the referees need to be held to the highest standard, and they need to be trained that certain things are just off the table - and this is clearly one of them. I would expect any mature person who is in his position to understand the context and not refer to someone as 'the black guy'.
2) This tendency to move the argument to an extreme and exaggerate to the point where we start claiming that "we cannot use the word black now" or "if someone refers to me as white should I be offended" is quite old, and just unnecessary. It's a fact that black and other minorities have been the ones that have faced discrimination and racism by Caucasians for generations and hence there doesn't exist the concept of 'white shaming' someone. I am not going to get into this point further, there's enough out there one can read and watch about this, but yeah, just wanted to point that out.