I'll give you guys a little perspective from the other side of the fence, no pun intended.
I grew up in the poor part of town, and most of the kids were heavily into gangs. Most of the guys I grew up with are either dead, and the other half are mostly doing life sentences. A few of them got out on parole, and I'm close friends with two, who changed their lives around. Both were in for very serious felonies. One had a triple murder, and was only released on his 25th birthday because they couldn't keep him any longer according to state law.
Your actions do have an impact on their future well being. I know, because they still talk about certain staff and COs 20 years later. They remember some and speak the names with a little smile, and some are probably lucky they weren't found by these guys. You're not going to profoundly change their lives though. That comes from within. They're definitely not going to say Mr. papacarts was nice, so I'm going to give up the gang I grew up with to become a wholesome person. But if Mr. papacarts wronged them in any ways, it just adds another straw to burning pile of reason they're going to make the world a miserable place.
The best that you can do, is to set an example by being decent human beings. Most people aren't equipped to deal with these guys, including the psychologists they've been assigned. I am not excusing their actions, but some of the issues that they've dealt with go far beyond what most people know how to address. The two guys in question, were war refugees. They've both been fighting since they were kids at refugee camps. They've been beaten to pulps by their peers, and by their own parents. They grew up in households where their fathers would grab them by the ear and slam their heads into the wall for the slightest mistake, and beaten until they were black and blue. You can't fix people who have shot and stabbed others since they were teenage kids, with a few simple words. Just don't add to the problem.
Yes, some of them just don't give a fuck. Really, truly, to the core sociopaths. For what it's worth, people can, and do change. That guy with the triple murder has a family and kids who are now attending AP classes. The other guy is trying to right all the wrongs he's made in the world one step at a time. They're little steps, but ones in the positive direction nonetheless. He has volunteered at charities for disabled people, helped children at Sunday schools, donated his income to St. Jude's, etc. An ant crawled into his townhome once, and he let it get on his finger, then walked outside and blew it into the leaves. "Life is brief and valuable". Even killers, can eventually see the light, and want to repent.