They didn't escape gang violence they just went to the most professional gang that offered the best benefits.

There's a real contradiction between how leftists view traditional crime and how leftists view service in the military. Say someone was affiliated with a street gang in their youth and really got in deep at 17. Maybe they didn't personally kill anyone, maybe they weren't even directly involved in a murder, but they worked for an organization that murdered and harmed people. A lot of leftists will emphasize how that person was a kid when they joined, the economic circumstances they grew up in, how limited their personal role was, etc. There's truth to much of that, but we're also talking about a largely self-interested pursuit that largely hurts people. But if that person's twin joins the military at 17, maybe after participating in some sort of ROTC program for a few years before? Then they're not a kid, their circumstances weren't desperate enough, wouldn't a Nazi sweeping floors at a base still be a Nazi, etc.

A street gang isn't the same thing as the military, but we can't correctly note all the similarities and then treat them completely differently.