>It seems contradictory to care immensely about [school] safety but lament the idea of wearing a [bulletproof] vest to [enter] the [school].
(Or be subjected to a metal detector screening, etc.)
No, it's perfectly consistent. The argument is that the underlying problem shouldn't exist to any significant extent in the first place, and doesn't need to (and doesn't in many other parts of the world).
A lot of traffic safety issues in North America derive from road design, which has historically prioritized the needs and wants of car drivers above everyone else. It is not "contradictory" to reject a solution that entails doing even more to accommodate cars.
