I have worked very closely with lots people who are currently incarcerated for violent crimes and while there's definitely shitheads there, there is also a lot of people who made mistakes and didn't have the structure and support in their lives to avoid getting to the place of making that mistake. Most of these people would not have committed violence if they had the proper social structures in place throughout their life - supportive family, friends, mentors, and peers that allow for meaningful personal development and mental tools to deal with life's difficulties in a healthy way. A lot of it wouldn't happen if there wasn't financial constraints that prevented that healthy development. Growing up in survival mode is a traumatic experience that many people never recover from. And many people are driven into a place of desperation and extremes when they lack basics for themselves and their families.

They're all humans. Humans are largely a product of their environment. Sociopaths obviously exist, but most people in prison for violence are not sociopaths.