Racial discrimination at Duke University's Biostatistics department
I believe that for the students the situation has resolved itself. But I expect that it was collective action on the student's part that brought it to the attention of higher powers. I might be wrong in all of this, of course, but I think that people have been made sensitive to the problem and will be less willing to engage in (blatant) discrimination. 

So, it may be that in the short term, things will improve. 

But in general, it is collective action that is needed to bring such things to the fore. Bad things can happen in dark alleys. The light of day is a good disinfectant. But when someone powerful is acting badly, individual action might only make it worse for the individual. There is power in numbers. 

If the students are still threatened, it is good to stick together. 

Individuals can, of course, seek reassurance from their professors. If it isn't forthcoming, more light is needed.