I currently work in a prison and agree there should be a minimum age of 25 to work there. However.... the turnover is huge and many are permanently recruiting. Many senior officers were made redundant during cuts years ago and now with an ever growing prison population the need is desperate. A tale as old as time in many professions.
Some prisoners are themselves vulnerable and many are very very manipulative. They often have years to build up and groom and individual(s) Flattery, starting small and testing boundaries. I have a rule i stick by... if I do something for a prisoner I have to be prepared to do the same thing for every prisoner. No special treatment and yes, it can be tempting as some pull on the heart strings and often have devastating childhoods, trauma and addictions.
It isn't all bad. I've seen many turn things around and met many good hearts.
The media love to paint an awful picture prison isn't easy, it's tough, and horrible. Working in one for me is an honour, and very humbling.