It's an apples and oranges comparison in the first place. There are security expenses related to prison populations. You need staff, facilities, equipment, etc.

It's an apples and oranges comparison in the first place. There are security expenses related to prison populations. You need staff, facilities, equipment, etc. to manage prisoners behavior (prevent fights, etc.) and keep them from escaping. The two things have a different mission, so of course they're going to have different costs. It's like saying a refrigerator is more expensive than a microwave. It doesn't mean anything because they do different things.