I think a large amount of 'normal' people don't communicate as much as you think. They have other people they talk to instead, whether that's a therapist, family, best friend etc. Somethings just aren't worth rocking the boat.
To say just Japan has a communication issue is just weird. And in the case of this MC he's suspecting to get a response he doesn't want to hear. So he won't ask, because people aren't logic robots, they're emotional humans.
