I'm not sure this qualifies as a question about philosophy - at least not "deep philosophy." Your question focuses largely on common sense and political correctness.
The key words are attitude, context and interpretation.
Identifying a bassist as "the white guy" can be perfectly fine in some circumstances and a little dodgy in others. Let's ask a pertinent question: What would be a better way to answer the question "Which bassist?"
Suppose there are two bassists, one white one black. The white bassist normally wears blue jeans, while the black bassist wears a suit.
You could now answer the question like this: "The bassist who wears a suit."
But we now have a bit of a paradox. To me that sounds kind of weird. Are you afraid to mention the fact that this guy happens to be white or black?
And are you sure the person you're talking to is aware of how the two bassists dress? Come on, the most obvious clue to their identity is their race!
If one bassist was male and the other female, would you identify one by saying "The one who wears a dress"? Of course not, you'd say "the woman."
So what makes race sleazier than gender?
Given the fact that racism is a painful (and often complex) reality, there are situations where you have to be careful. If you refer to someone as "that black guy" rather than "a black man," some might interpret it as an insult. On the other hand, if you're talking to a black person who knows you and understands "where you're coming from," then saying "a black man" might sound a little formal and pretentious.
As a former teacher, I learned that black people in Seattle - which is a surprisingly racist city - can be pretty sensitive to this type of conversation. However, most people who are reasonably intelligent should normally understand what a person is saying, and if they have a problem, they can observe that person more closely before pronouncing him or her a racist.
In fact, my observation is that the people who are most prone to label the type of conversation you describe racist are trouble makers. In my case, they included some parents who had problems of their own and school officials, many of whom can in turn be described as "Uncle Toms" or "controlled opposition."
The place where I currently work has a lot of problem people on the payroll, both white and black. If I call Dylan a jerk and someone asks "Which Dylan?" I have no problem saying "the white guy," "white Dylan," "black Dylan" or whatever. And it doesn't matter if the person I'm talking to is white, black or Asian.
However, if I want to talk about the Seattle School District's "Black Mafia," I have to be a little more careful. We're now talking about a more sensitive topic, one that sounds a little conspiratorial.
In fact, there are black people I work with who know exactly what I'm talking about - especially if describe members of this informal organization as Uncle Tom's or sellouts.
But if you were a candidate for public office and you mentioned the term "Black Mafia," the corporate media (which are themselves racist in the extreme) would promptly condemn you as a racist.