Earlier quoted context omitted.
Prison is meant to be a deterrent to crime, don't do the crime if you're not prepared to do the time. Last I checked no one is rounding up innocent people and sending them off to the gallows.
Then last time you didn't check very well: https://www.youtube.com/watch?v=Cdvy14fdjj8 Besides that, slavery its not one a valid punishments in civilized nations.
It's the brutality and the length of sentence that may make it bad.