Blacks disproportionately commit crimes because Blacks are disproportionately poor. Blacks are disproportionately poor because Blacks were literally enslaved, and then oppressed via the legal system until just two or three generations ago. Anyone pretending like that generality is wrong or difficult to understand is stupid, racist, or some combination of both.
I tell you what - I consider myself a fairly enlightened individual and it was sumpin' going back through Ancestry.com, watching the census reports, finding ancestors that owned slaves, and deducing that not one, not two but three sets of grandparents became itinerant farmers the minute their slaves were freed. Going back to 1827. And I mean... we're talkin' plantation owners who were in positions to sell their plantations. Not people with nothing who all of a sudden weren't in chains? But also weren't picking and choosing from a cornucopia of career choices. Give or take two or three generations...and then oppressed via the legal system until just two or three generations ago.