Black people really do commit a lot of crime in America, it's not just a "stereotype". And particularly, young black people, and particularly young black males. Black males between the ages of 14 and 24 commit 27% of all murders, despite being 1% of the population.
It's not scrawny white twitter engineers who are shooting each other in San Francisco
It's not entirely race. I'm certain that e.g. poverty and lack of opportunity play a role as well. Growing up without access to money, good schools, or positive role models can be crippling to success regardless of race.
Poor whites and Hispanics aren't nearly as dangerous as poor (young, male) blacks. There is not another comparable group that manages to commit 27% of murders as 1% of the population. That's a huge ratio.
Keep in mind, most black males will never kill anyone. But black males commit a plurality of murders in the US. And 1 in 3 will spend some time in jail in his life. 1 in 7 American black men are in jail at any moment.
Remember, there are more whites in poverty than total blacks in the United States, and blacks commit 48% of murders.
If you're in an urban environment, don't be a progressive hero and try not to avoid young black males. It can be dangerous[1][2]
It's not scrawny white twitter engineers who are shooting each other in San Francisco