This is a hugely difficult area, were each of us brings our own baggage so to speak. Unfortunately, there are a small but vociferous number who use the issues and tensions - real or imagined - for their own ends. Largely secular, these include the far and unattractive right and the 'social engineering' left. Both tend to use broad stroke issues and particular incidents for their own ends. Any individuals are to be cynically used and discarded. This is not Christianity!
When in Greece I met Old Calendarist monks born and raised in central Africa. It was a reminder their is neither male nor female, Greek nor Jew, among us.
As to Bill Cosby's comments, they sadly could be applied to the poorest whites around here. The difference being that the inability to communicate by poor blacks is likely to be upheld by some as not a problem but society's failure to recognise their equally valid language form? Quite how the social engineers arrive at this conclusion escapes me, and no doubt others!
I sometimes have to challenge other people's behaviour towards members of one or other minority. The most recent incident happened 10 days. The person challenged, resentful about it, asked whether I was doing so because of some 'politically correct' attitude on my part. My response was, "No, it was because of something I percieved as an expression of conscious or unconscious bigotry. And as our disability organisation was supposed to welcome all, such expressions clearly had no place". Sadly the person concerned could see no further than this challenge being an expression of 'political correctness'.
So-called 'political correctness' is something I some grave reservations about. It appears selective and politically motivated. It has one particular characteristic I really struggle with, which could be summed up simply - "The intolerance of tolerance". Paradoxically many of those who advocate it are children of the enlightenment who greatly critizise believers, especially Christians. They talk of Christianty's closed belief system, with its ridiculous dogmas and lists of cardinals sins. But in what way are they different from that they supposedly understand and freely critizise? For me the guiding principle of accepting my neighbour is much better illustrated in the Parable of the Good Samaritan.