It’s really not that hard to figure out. Poverty and crime are very highly correlated. Surely you know that for hundreds of years, Black people were not afforded the same educational and employment opportunities as white people. They were also discriminated against in housing and essentially excluded from living in white neighborhoods. This stuff was still going on when your parents were still alive - so it’s not like this is ancient history. So for generations, you have neighborhoods full of black people living in poverty, which of course leads to an increase in crime.
What do you think happens when there are neighborhoods with an increase in crime? Obviously, the police spend even more resources in policing those areas, which leads to finding even MORE crime - so police keep sending additional resources to patrol those areas. This leads to over policing - now when people in these areas commit even petty crimes like marijuana possession or shoplifting, they are much more likely to be caught than people in wealthier, predominantly white neighborhoods. This causes police to begin stereotyping black people - they are finding more crime in black neighborhoods (in part because they are looking harder in black neighborhoods), so police become more likely to suspect black people of committing crimes.
Of course, this also causes black children to be more likely to grow up in single parent households, which is also highly correlated to crime and poverty. And that isn’t even mentioning that most funding for public schools comes from property taxes, so schools in these neighborhoods are woefully short on funding. Lack of educational opportunity is also highly correlated with poverty and crime.
Then, we have statistics showing us that black people (men in particular) are more likely to be convicted, and more likely to be sentenced to harsher punishments than white people, for committing the same crime - even when you account for prior convictions and other extenuating circumstances.
LOL at thinking all this goes away if black people just start taking more “personal responsibility.” As someone in this thread pointed out, this is hundreds of years of systemically oppressing black people. The deck is stacked against many black people to succeed. It doesn’t mean they can’t, it just makes it way, way more difficult.