Eh.. even if you are him its a reasonable question. I can't speak for all staff members though. In general I'd say that part of the answer lies within the Harvard/stanford (not sure which) study. If you remember that is the study that had a bunch of college kids take on the role of jailers and a bunch of kids take on the role of prisoners. Even if they weren't prisoners or jailers in real life a whole crop of problems broke out.
Simply to say is power corrupts.
Programs that don't have a great deal of oversight are even more susceptible to abuses as who is watching? Eckerds wasn't perfect given they've killed a kid and hired a pedostaffer of late, but they do have a fair bit more oversight than places like Three Springs. Shit still happens, but far less shit happens because everyone knows that someone is watching.
Training is another issue..
You train people to respond to violence from the charges in certain ways you'll get a predictable reaction. So you have a place that emphasizes restraints over talking, and add in a lack of oversight and it gets ugly quickly.
As to why staffers abuse people in programs? That's a tough question.. I think alot are merely reacting to their surroundings and trying to do the best job that they can. They typically don't last very long, but those that do, in my experience usually end up burning out.
Others are sheer fucking sickos that get their jollies off hurting people. Others are simpering little program zombies who never think to question the program. I'd have to say that you are better off approaching the system they are in first and then the specific person second. Understanding the environment they operate in helps go a long way in understanding what prompts a person to carry on in the manner that they do.
I'd also suggest considering that most kids who abuse their peers in programs don't go onto be abusive people in the outside world. They merely were reflecting their environment and this is true with most staff as well. Not all, but most.. Most go on and live normal lives doing regular jobs and wouldn't dream of hurting anyone as they don't exist inside that corrupt system.
I'd wager to say that most of them who recognize what they've participated in go in the world to be wiser for the experience. Those who don't recognize that they've perpetuated the cycle of violence in a program are the ones I worry about.
Anyhow, gotta run.. I'm technically on hiatus as I'm in the midst of some real world issues. Why don't you get on yahoo messenger and we can chat?