Earlier quoted context omitted.
They have a duty to their shareholders to grow revenue and stay in business. If something threatens that, they will fight it. Like many other commercial enterprise they will spend money on lobbying to protect profits, in this case it is just particularly sickening how big the problem has become. https://www.youtube.com/watch?v=QsBDvxy5qQY
You just proved my point! Doctors who work in a group practice have a fiduciary duty to grow revenue. Does that mean doctors cut corners to make more money? I'm sure some do. Do private prisons fight relaxing laws to make more money? I'm sure some do, but most don't.
Corrections Corporation of America does, and they account for more than 80,000 of the 133,000 private prison beds in the US. GEO Group does, and they account for about 49,000. Together they thus represents the vast majority of private prisons in the US.
Both of them are part of ALEC - a DC base lobbying group that develops model legislation that it then pushes as a means for state legislators to be "tough on crime".