I think that the root of this goes back all the way to Zen-type of thinking. In Zen, it's often taught that mind is elusive/delusive and action matters. "Mindlessness (mu-shin)" is often thought of the best way of carrying tasks, and I see a similar principle in many traditional martial arts/craftsmanship; a new learner should just do certain tasks without thinking/questioning, and eventually their muscle memory will learn it. It's conceivable that people applied the same principle for safety.
I also think that this illustrates the difference between the Western religions and Japanese (or Asian) religions. Western religions are mostly declarative; you need to believe such and such statements. Whereas Japanese religions are procedural, i.e. doing rituals is more important than believing.