#1 is complete conjecture. You have no evidence to support your assertion. 

#2 It is actually 13% of the population but 40% of prisoners. Not only are your numbers off, your claim was that they commit 50% of the crimes. 

The fact is that although there is no difference in drug use and sales between white and black people black people are three time more likely to be arrested for drug offenses and 10 time more likely to be incarcerated for drug offenses.

When black and white people are convicted for the same crime, blacks receive sentences that are 19.5 percent longer than their white counterparts. https://www.wsj.com/articles/SB10001424127887324432004578304463789858002 in addition black men are 25 percent less likely to receive sentencing below guidelines.  

Black men are roughly twice as likely to receive the death penalty than whites, 77% of all death penalty sentences occur if the victim was white even though although blacks make up about half of homicide victims. Cont...