Let's see,

1. More fatherless homes
2. High amount of surrounding crime
3. Crappy education in inner cities
4. Cities mostly run by corrupt Democrats
5. Demonizing people like Candace Owens or Ben Carson if they leave the Democrat plantation to control the leadership in that community, leaving the likes of Maxine Waters and Al Sharpton in places of power and influence
6. Getting held to a lower standard by libtard politics, getting taught propaganda about systemic racism, getting told if you break into a store in a BLM riot, it's reparations

Actually no matter how extreme those may be, none of those things are excuses for a violent crime, especially the type in the OP. But it would be odd if it didn't increase the proportion of criminals within a society.