[moe]

Because it's obvious?

Anything to enable social interaction for him would have to happen on top of solitary confinement (or equivalent security) after all...

[baddox]

On the contrary, it's obvious to me that solitary confinement is significantly more expensive per inmate than non-solitary high security imprisonment.

[moe]

So how do you prevent the inmates from killing each other without separating them physically?

[baddox]

You can separate them physically without putting them in solitary confinement.