The reason poor people act like this is because they literally don't give a fuck. A lot of people are brought up with the mentality that they can't do any better and won't ever be able to do better, because no matter how well they do society won't accept them. In part they're right, society won't accept them, because they weren't brought up to be part of "the other peoples" society. They have no idea how to function in it so they lash out. Being mostly uneducated it tends to be more violent than an a way an educated person would lash out. Not that this excuses their behavior for randomly attacking people, but it kind of explains it.
I'm normally wearing dickies, chucks / adidas, tshirt and baseball cap. I've dressed like that for probably 2 decades and now I have enough money to live in a "nice" community if I wanted too, but I honestly don't share a lot in common with the people that live there. I didn't grow up going to good schools, living in a good neighborhood, their social circles, and I don't leave my house everyday at 7 and get home at 6. I have long hair and tattoos and since I don't look and behave like them they assume I'm selling drugs or doing something else illegal. The police bother me and people file complaints for shit they imagine. I don't want to change who I am to live there with out being harassed. If I walk into a Channel, Louis Vuitton, Gucci, etc store people literally walk away from me, because in their mind I shouldn't be there. I'm not dressed like them and they have stereotyped me with out even hearing a word that comes out of my mouth.
The poorer communities need positive male role models reintroduced.