Prisons break laws constantly, they are expected to violate rights, violate laws, etc... they are there only for punishing poor people.
Show me millionaires that are in prison that go to general population prison.
Um... not quite. Rich people are less likely to go to jail period (because they can afford better lawyers, are targeted less, and less frequently have incentive to commit crimes like bank robbery and burglary that get people caught). You really have to look at rich people who are convicted of burglary and poor people who are convicted of burglary before saying that the jails really just exist to punish the poor.
As for rights, yes, prisons frequently violate rights, but consider the *flipside* of that. In the United States, we make it relatively easy for criminals to *sue* for violation of their rights. So pretty much *every* prison guard, no matter how good or honest, gets sued by prisoners. It's not like prisons are trying to violate rights--they're generally trying to not get sued.