In all seriousness, it again comes down to cultural differences.
Chinese people can be absolute fanatics about respecting boundaries that are entirely imaginary to Westerners, while at the same time being completely oblivious to boundaries that are perfectly obvious to the rest of us.
Intention vs facts is the best I can come up with. It would be horrible to admit a bad intention, while no immediately perceivable fact could be construed to cause embarrassment (i.e. "but he is fat!"). Think of them as Vulcan clowns, if that helps. So you can observe or ask anything with impunity (e.g. how much money do you make), but you should always have a socially acceptable excuse for your actions ("no, i wasn't peeing on your foot, but it was on fire and i was trying to help. and i peed a little").
My in-laws are Chinese, so as puzzling as it is (and it is), I'm not the least bit surprised at this. I'm still trying to understand it, myself.
There is a logic, it's just backwards to my way of thinking.