Er, that's called solitary confinement. It's typically reserved as an extreme form of punishment, considering humans are social animals. Put any prisoner in solitary confinement all the time and they certainly will want to kill themselves. Disagree. With no weapons and superior strength, a prisoner can kill a guard simply by bashing their head into the concrete. Humans are fragile. Sounds like a great idea. Put it on a ballot and I'll vote for it. Until then, with the environment we have, prisoners are dangerous. Laws should consider the reality, not the ideal.Inmates would never interact with each other, or even with guards except remotely.
The human animal is not, biomechanically speaking, that dangerous.
With automation, and sufficient industrialization, a proper prison