I think it depends on your surroundings.
If your a first generation citizen like myself, then your parents are more likely to teach your black history and ancestry, but if your not and your grandparents and those before were settled already and assimilated then I can see why most parents would skip the black history lessons.
My father made sure he schooled ALL his children on our linage and history
In the UK, most black people are first citizen born from African or Carribean parents (Africans more than Carribeans)