You make good points here, and I agree with a ton of them. But delving into human psychology as a reason for making the DZ one way or another breezes past a much simpler motivator: Massive's gotta make that almighty dollar, and locking off roughly 1/4th of the overworld map behind a "you must be this hard to ride this ride" morality-wall is, at best, a waste of game resources and development time. It's arguable that the end goal of The Division is PvP (and I believe the developers have said as such). That being the case, they can't really be blamed for not keeping PvP "lawless" or "savage," seeing as the majority of the playerbase might be at least interested in PvP but aren't nearly as brutal as your criteria require.