First part isn't exactly true; http://nces.ed.gov/nationsreportcard...es/2009455.pdf - page 6 and onwards. There's quite a large gap.
On the highschool part, it's probably a combination of:
- Media/liberal education pushing blacks in a victim postion, painting whites/white society as evil
- Typical popular Worldstar culture
- Upbringing in a fatherless family
- Some genetical factors