It's not a deliberate policy. There's precious little else to put your money in so the Chinese end up using property as a savings account.

Developers will often skimp on construction quality as a result, since they know that nobody will actually be living in them.

You seem to have read the western propaganda that has misrepresented the situation: https://en.wikipedia.org/wiki/Under-occupied_developments_in...

In what way is it a misrepresentation?

Thats just a link to a page on ghost cities.

Yes, and often those cities will be torn down before they are actually used. It’s all good: turns out demolition also counts as positive GDP in their statistics.