Here‘s an argument: The US is supposedly the land of the free, where everyone is allowed to live life according to their beliefs. It would be against this principle to force this re-education program you‘re proposing on someone.

A way simpler argument would be that it‘s unrealistic to expect this level of discipline for a stretch of time like this from people who couldn‘t even stop themselves from killing someone.

However, if you‘ve ever read „Papillon“, I think the methods he describes as using in dealing with his sentences seem to me to be pretty close to meditation.