Yep. That is what happens in most cases. Which is why I reject the idea that most cops which shoot black people are racist. Sometimes, as is the case of George Floyd, the individual officer is at fault (even if that does not _necessarily_ mean he is racist), however, in the vast majority of police shootings, the victim is trying to reach for the cop's gun, assaulting the officer, or in some other way is putting the officer's life in danger. So you can not blame the individual shooter in such cases.
You can, however, blame the systems which cause the erratic behavior, that's true. However, we need to have an honest conversation about what the causes actually are.
The gang culture in prisons is indeed a problem, but making prisons less tough would not solve this problem - it would only exacerbated, as gangs would have increased influence over the prison. Of course, in reality many gangs are in cahoots with the prison staff, which is a corruption problem which needs to be solved.
Another problem the article correctly points is non-violent offenders becoming violent as a result of their time in the prisons.
That said, the gang culture in prisons is only an extension of the gang culture outside of prisons. And you can not blame that on tough sentencing, as the gang culture exists in many other places around the world - in the UK grooming gangs, in Sweden's no-go zones, in Romania's gypsy gangs and so on, all countries without harsh sentencing.