Like it, QOD. There's a story in my family that my uncle (this is back in the 70s) had to describe over the phone to his bank manager a description of the man who was bringing in a cheque. My uncle said "he's wearing a grey suit". He didn't like to mention the hair lip because the man was sitting in the same room.
"you bitch" is acceptable. (possibly not to the 'bitch')
"you black bitch" is not.
"He's black" is acceptable.
"he's the black bastard" is not.
It is true that people of colour of any kind are mostly in a minority in the UK at the moment. As that evolves and changes, it will be a less-useful identifier, and then it will die out naturally, won't it.
When I did diversity training, they said that people don't generally find compliments which are all inclusive insulting. So 'black men have big dicks' or 'Asians work hard' generally ok. "Yanks are loud", "French are cheese-eating surrender monkeys" not so good!
I quite like "political correctness gone mad", because it makes us think. To my utter, utter, utter shame, I used the term "half caste" to a black woman about 15 years ago. She was describing a youth group and I was struggling to understand who was welcome to attend it, and I'd not come across the term "BME" before. When I said "Oh... you mean half caste" and saw the look in her eye, something inside me died. I felt like everyone's granny... the world had changed and I hadn't noticed. (one of my best friends at school had a black and a white parent, which was rare back then, 10,00000 years ago, and she was often thus described. Not by her, I now remember)
And what kills me, even today, is that this woman went away from what was supposed to be a very positive meeting thinking she'd just met a racist.
I think about the language I use very carefully!