A Bridge Too Far?

I don't understand all the fuss about this bridge collapse in the USA. Surely everybody realises that bridges are not held aloft by pillars of steel and concrete, as scientists like to pretend, but by the magnanimous benevolence of Baby Jeebus. Obviously, if there are enough non-believing infidels on a bridge at any one time, it will collapse. How else to explain why 70,000 other US bridges, similarly graded as "structurally deficient" remain aloft?