@brass_max , you're on the right track but missing a few things.Gun free zones only work if they're enforced by trained, armed security with weapons detection (metal detectors and pat downs). This is only preferable to allowing CCWs when
1. The likelihood of an attack or the potential damage of an attack is too high to risk any one having a gun.
2. If the gun free zone in question is given the resources to adequately be enforced.
3. The gun free zone designation doesn't significantly interfere with the processes of the enterprise/institution. Example: Slow security screening process making students or employees late to their jobs.
I can think of two: Government buildings and sporting events.
Gov't buildings. The people in your local courthouse, your state congress, and the White House are there represent American democracy and their political power is vital to our system working. They are too important to put at any risk. Dedicated security force and metal detectors are best here in my opinion.
Sporting events. Super high concentration of people makes arenas very vulnerable to a shooting. However a CCW holder is just as likely to shoot someone they didn't intend to if something happened. And "something" is more likely to happen if people have an easy time getting guns into the venue. Again. Dedicated, trained security force and weapons detection is best.
Everywhere else SHOULD permit guns to be carried. Everywhere else is either less important, less at risk, or cannot fund or adequately employ security. Campuses fit the bill here because they either don't have security or they don't have enough of it. Campuses are pretty big. One CCW student in each classroom is better than one underpaid/trained security guard in each building. My $0.02. Also having TOO much security can become oppressive in certain environments like schools, in which case I say let the students staff and faculty defend themselves and each other.
I took an hour to write this it and went through four drafts. It's an interesting and complex topic.
A GFZ can only work when the entire perimeter is secured. Do you know any college that is securely fenced in? Any K-12 school that's really fenced in? Didn't think so. So most every GFZ is a very leaky sieve.
Government buildings and Courthouses as GFZ? Why? In many places, the "courthouse" also has many other administrative offices where people have reason to visit. Why should all city/county affairs be in a GFZ? They are, after all, "The People's Places", like most all federal facilities. I'll grant that the courtrooms themselves as well as adjacent offices and hallways could/should be secured. But it should be the least amount of area feasible.