https://reason.com/blog/2015/06/02/are-for-profit-prisons-or...
Most likely the reason for this is that private prisons enjoy no monopoly position; why lobby when others will capture the benefits?
Generally you're going to find very, very, very few people that are willing to have a facts based conversation on the topic. The popular narrative is to pretend that private prisons have driven the population boom - having a single digit share of the total prison population 15 years ago - despite the fact that it was overwhelmingly the government prison system and government employees that pocketed all that money the last 40 years.
Anyone here want to run rough numbers on how much combined income the millions of government prison and related workers derived in the last 40 years? Or tally how many millions of government jobs were created over the decades by politicians by putting millions of people into government prisons (and keeping them there)? It's trillions of dollars that the government has paid to its own workers, between the government employees putting prisoners there, and the government employees that keep them there. Accordingly, nobody could possibly have a larger vested interest in the prison boom than the government.
You are correct to note that public prisons are just as bad. Prison guards, companies that supply public prisons, police, firms that contract prison laborers, etc., are just as greedily pro-incarceration as private prison shareholders.
From this position of wisdom, what is the optimal communication with people who are against mass incarceration and excessively anti-privatization?
Is it to attack them for being ideologically blinded? Or try to convince and coalesce with our natural allies?
If someone is ignorant of a truth that is plain to you, you get to decide if they are a friend or an enemy.