I've ridden for years with the Dutch mindset - I kept a '60s steel roadbike rolling with a bent frame after a car hit it while locked on the sidewalk (ugh). Frankenbikes can be great, and the performance limitations give them some personality, especially if you're already a comfortable cyclist and understand (or implemented) the quirks.

But there's a big difference between the 'keep it rolling' mindset and dealing with new-from-factory plastic that walmart et al try to pass off as metal. I've seen axles split in half while coasting down a steep hill, dropping the bottom bracket straight to the ground (and the rider along with it). Derailleurs pulled into spinning spokes, causing an explosion of twisted metal that was thrust into my friend's calf.

I think a lot of the safety insanity you refer to comes from most American cycling experience being on bikes that seem designed to fail spectacularly.