> the people rely on each other to enforce social norms

This is probably the difference.

Here's a video of a leading UK MP (whose party largely represents upper-middle class white-Brits) reacing to someone doing something he doesn't like on public transport:

https://www.facebook.com/libdems/videos/stop-the-headphone-d...

Note the passivate aggression, then the threat to use state force to stop it.

British people are too polite to tell people to stop doing things. We prefer that to be a responsibility of the police.

The thing is, Japanese are also typically very polite! For minor violations of social protocol, you’re most likely to get a polite request or indirect reminder from someone. (It would be rude to make someone lose face, even someone who is violating a norm!) Yet somehow it works.