@JellySlice
A black man or woman announcing that he/she "identifies as white" would be laughed out of media and mocked...
Why is it that a person with dual heritage, one black parent and one white parent, can identify as black, but cannot identify as white? Is it about society's perception of them? Would it be different if they were in, say, Botswana?
It goes back to the "one-drop-rule".
www.psychologytoday.com/us/blog/in-the-eye-the-beholder/201104/the-one-drop-rule-how-black-is-black
Back in the day, anyone who had even a drop of "black" blood, say, a great-grandmother who was a slave, was tainted and considered black, even if you looked white. It would be a huge thing -- and if it was uncovered that you had such a great-granny, it would spoil your marriage prospects and destroy your social standing. A touch of the tarbrush was the going insult.
In my country, white was the dominant culture, even though they were just a tiny minority, and the superior culture, at the top of the multi-racial hierarchy. But you could not just claim whiteness, and you still can't. I'm not from Botswana, but a mixed-race person in my country cannot just "identify" as white and get away with it perhaps if their skin was indeed lily-white and no-one suspected the touch of the tar-brush it might work.
Growing up in a black-majority country, I witnessed and experienced a lot of this as a child. In a way I did identify as white: all the books I read had exclusively white characters, I knew English and American white culture as well as my own (because of books and movies, which were all about whites), the schools I went to were always majority white private schools (my parents' choice) and I always "felt" I was the same as my white friends, no different at all except for the fact that I carried around a deep sense of inferiority. Because my skin colour still identified me as "other", and I was made acutely aware of this.
In the end you cannot identify into more privilege. That has to be granted you by the privileged group, and that hasn't happened. White is still the privileged group, even 60 years after civil rights struggles.