It's the taxpayers putting him in a cage. The taxpayers should have to pay. It's like if Mormons decided you needed to be caged for questioning the golden tablets, then tell you that you have to carry the costs of the Mormons' violence on you.

If the taxpayers were smart: a few US states worth of land would be converted into a Gaza like reservation, where the only guarantees and service are protection from invasion and suppression of any gang which gains a reasonable monopoly on violence. It's fenced, with security and ports of entry and exit. Citizens can come and go, outlaws can only come until status is restored or they leave the country (re-entry to be denied). Sentences become time there instead of fenced concrete camps. Now you have a mechanism to fix prison into a rehabilitative hospital and job training system, which is voluntarily elected in lieu of the outlaw badlands zone.