They've done studies on this.
The American negro is unique in the world. He is the only minority who suffers complete academic, social and commercial failure yet appears very self-confident and assertive. Every other minority in these same circumstances feels inferior and developes self-loathing.
The reason, I guess is the constant brainwashing about kings & queens in Africa, bogus and incorrect claims about black history and the belief that their failures are due to events of 150 years ago and a racist conspiracy to oppress them.
Ever wondered why even monor criticism of black culture draws such outrage? Ever wondered why they hate Jews and Asians so much?
Pointing out the realities of black culture reveals a simple truth that they are unwilling to deal with. It contradicts all their myths and excuses. Similarly, Jews and Asians are a minority who have been slaves, victims of racism & hatred, called names etc etc. Yet they all make out good, and achieve social, academic and economic success. Their very existance disproves all the blacks slavery/ racism excuses for his failings. The truth always hurts.