No, housing isn't expensive in Japan, certainly nowhere near how bad it is in US cities. Housing prices are more or less flat in Tokyo over decades, even, because they constantly build more of it. (It's cheap in the rest of the country, but that doesn't mean much because nobody wants to live there and there aren't jobs.)

Not saying it's great; Japanese wages are too low and their landlords are abusive (moving is expensive, you have to pay a lot of "key money", and they're free to discriminate against foreigners). But the housing crisis is an Anglo problem - it's bad in the US/UK/Canada/Australia.

Not sure about France specifically, I was just saying Paris is a nice city.

High density housing isn't protected because we choose not to protect it. But that's changing, thankfully.

How is it disingenuous? OP asserted that communities are "allowed to decide how they are composed," and they obviously are not. Which decisions we allow communities to make is the entire question.