It's become more and more obvious over recent months that racism can be very nuanced at times. Because it isn't always clear cut and it needs to be contextualised, it means those who don't want to admit it exists or don't want to do anything about it, can deny it's there's by stripping it of context and making people's concerns sound absurd.
So yes, there are plenty of situations where it would not feel problematic to describe someone by their skin colour or saying "the black guy". But there are still plenty of situations where it wouldn't be appropriate. In a professional setting and in the midst of a confrontation I don't think it was a great thing to do. If, for example, you were at a customer service desk and someone was trying to return something, and the employee went to fetch the manager to put the transaction through. If when the manager gets to the desk and in front of lots of other customers asked the employee which customer it was and they pointed at them out and said "the black one", i think that wouldn't be appropriate. I think most would agree that that would be awkward. Perhaps it's the othering of people, or reducing someone down to the colour of their skin that doesn't feel right.
Along with that, it isn't always what people say. It's how they say it. It makes a huge difference.
Whatever the case, we'll have to wait and found out what exactly happened. And even then we might still not know.