>Look at Japan as a homogenous and extremely (if not the most) high trust society.

Why does Japan need separate trains for women, and why can the shutter sound on Japanese phones not be turned off?

All countries need this; Japan's just the only one that did something about it. I'm sure NYC ladies would love segregated cars right about now.

Um... why exactly am I looking for a highly homogenous society?

I'm just saying they tend to be more high trust, which is supported by statistical data.