Seriously guy. Prison is supposed to be a bad scary place you don't want to go. A lot of the things that are "allowed" to happen in prison are due to the fact that the country club mentality of the left have turned prisons into adult daycare's.
You keep saying that prisons function is to separate convicts from society. That may be one aspect but not the only one and it is a bit naive description of prison. Jail is a much better suited to you definition. The other aspects are punishment, rehabilitation (obviously works ), and public safety. Personally rehabilitation, if any, should come after prison but that's another debate. Personally I find my kids respond better to correction when I'm not giving them candy and free TV when they're in timeout.