shyt is honestly complicated as fukk. To really explain it would mean going through the in depth history of Chicago's gang subculture. And that goes back to the 1900s.
It's a whole subculture about mofukkas who have nothing fighting and killing over nothing. A gang will control a block, a rival gang will be on another block, they'll beef for shyt ranging from drugs, machismo, online disses etc...leads to fighting and eventually killing. Dudes retaliate and it quickly forms into a shoot or attack on site blood feud.
Doesn't help that most the gang leaders were locked up which had unintended consequences, along with the fact most the projects were torn down and project people spread over the south n west. This lead to new gangs being made, new feuds forming, even more hood chaos.
The police and city government in the Chi are extremely corrupt. The CPD has given out more money in brutality and malpractice cases than ANY other PD in the country. They have crime clearance rates of 25% compared to NYPD 75%. They even had a damn illegal secret black site holding facility, where they detained a tortured thousands. This year they brought down their stops and frisk rates 90%, just because citizens were unhappy with their prqctices. Worst police department in the country.
Chicago is also deeply segregated socioeconomicly. It's no coincidence the most dangerous neighborhoods are the poorest.
Basically mix a deeply rooted gang subculture, the most inept and corrupt police force and government in the US, rampant poverty, heavy socioeconomic/racial segregation, the worst and most defunded public school system in the US, easy access to guns, hella drugs to be trafficked, n dumb hood nikkas and you get what'she going on in Chicago.
If you want a better analysis check out a documentary or book
Bet you had no idea that the homicide rates back when whites were the poor ones in those areas wasn't much different.