As to the larger question, I'm having a very hard time seeing adding knowledge and science as a bad thing. Without those, any proposed improvement to policing (including abuse) is simply flailing guesswork.
In your view, these are people that don't wish to integrate themselves, and in my view, these are people that never had much of a chance to begin with. The public schools I went to were so underfunded, and I am lucky that I took a different path than the one of least resistance. A lot of the people I grew up with that joined gangs were abused as kids, had learning disabilities, grew up with violence, didn't have a proper learning environment, didn't have after-school programs to go to when they wanted to avoid violence and abuse at home, etc. I'd rather take money from police departments and funnel it to actually giving those kids a chance.
I had an early life typical of some of these places. My area was not as bad as the one you describe FYI. I made so many mistakes in my own early life that really set me back, some of which could potentially be attributed to the nihilistic attitude of my surroundings. As a result I'm perhaps more sympathetic to the downtrodden people of these areas than you might believe. That being said, my own success in life has made me slightly less sympathetic to these people than I used to be. I underwent a massive attitude change in my early 20s that changed my entire life. I stopped blaming other people for my problems and took responsibility for my life, it was like flicking a switch. All of a sudden everything in my life slowly began to function, I started to receive positive results from my actions. I understand that not everyone can become rich. You'll have greatly different results if instead of becoming a software engineer like I did you're just bagging groceries. That's always going to be the case though.
I truly understand that getting through to kids from broken homes can be difficult when their parents, like mine, have created such a hostile environment for their kids that they base their entire conceptual model of society on their broken home life. Having said that, there's no one out there telling people that getting hooked on hard drugs is a good idea, yet it still happens. These kids know what living a good life looks like. They make their own bad decisions. I really do believe in offering all the support we can to help at-risk children avert ruining their lives. They're not all going to be saved, no matter what you do. I feel like those who are capable, and interested, will always seek out better things for themselves eventually.
Many times throughout history gangs form for self protection in absense of a functioning authority. Regardless they inevitably get involved in a racket of some sort or assert their claim to some sort of territory and become just another band of violent thugs out for themselves and a scourge on their host community.
The remotely closest thing to a gang that hasn't progressed to that probably isn't like that are the Guardian Angels safety patrols.
Being brutalized is neither neccessary nor sufficent, although it may make them more likely. If the "configuration" arises essentially they will go down that path.
And as for making the right decisions--I have a few issues that have worked hand-in-hand to keep me from having a long and stable relationship. I know which bad decisions I've made in the past, I know as I making them that they're bad, yet here I am, single and at 31! It's something I'm still trying to work through. So having said that, I am not going to judge someone for their bad decisions if I can't always pick the right path myself. And I'm sure you're not always sticking to the right path, either. I mean, I'm sure there's a billionaire out that there could go through your life decisions and judge you for not having a fleet of yachts yet. It's easy to be like "don't do meth!" and then not do meth, but I don't know what those people are going through that they thought that meth was a good idea. I don't want them in jail for it, either. I think there are far better options.
> ...the issue is that society gives up on them before they even have a choice...
I was able to learn useful skills on my own without the education system supporting me. No doubt, high school helped build a useful foundation for learning other useful things. I was teaching myself skills using freely ( or the next best thing ) available tools and resources online. American poverty in 2020 includes access to the internet. This is evident by the interaction of impoverished and low socio-economic status Americans on social media. They're not here debating the systemic causes of poverty on HN, they're consuming mind numbing media on worldstarhiphop. Before I was able to get internet access at home I used the local library, or at my high school. I won't dox myself by talking about my specific professional interests, save to say they were important enough to me that I devoted my own time to researching it. I refuse to believe that there are people in first-world countries who have no access to useful resources like this. YMMV, obviously. I didn't have anyone in my life who encouraged me to do X, I just felt X was cool and I really wanted to understand more. Most of the people I've met in my field are the same. I don't mean to project my own thoughts and experiences on to everyone. I feel that my natural inclinations were to learn, and all of the people I grew up with who were similarly gifted and inclined ended up escaping poverty in one form or another. You could probably count yourself among this cohort.
Throwing police at the problem is only putting a band-aid on the symptoms, but ignoring the root cause. Violence will only beget more violence in the long run.