The topic is interesting. We have a variety of mixed folks in my family, everything but Asian. How they've chosen to identify themselves seems to be arbitrary. One neice identifies as mixed, the other as white, both have the same parents.
My brother boys are half white and black but too young yet to choose how they identify, if they choose at all. Their mother is black Dominican but identifies as Hispanic. For my brothers family, being a catholic is stronger factor in terms of identity than race. I expect the new norm to be identifying as both or neither. The pressure to choose is lessening, especially for the younger generation.
Ok, we can now return to racism.