I apologise in advance if the following points have been addressed already. I just couldn't bring myself to read 13 pages of thread.
It is indeed much more common in Chinese culture to stare than in other countries. That is because the concept of privacy is adopted by relatively few members of society. Some of the more rude individuals would look at people from top to bottom and then up again. It's not just pretty girls or foreigners who attract stares. They pretty much stare at anyone they want to. They feel it's their god-given right.
I have on many occasions challenged individuals in this regard. They would remain silent and attempt to maintain a fixed glaze in defiance, but once I get more aggressive and move up closer to them, they would back down. While many want to "save face", they are reluctant to actually get into a physical altercation. Obviously I have not attempted to challenge dubious triad-like characters. It's also difficult if the situation involve old men. They are the most belligerent, and they are confident in the knowledge that no one would attack them.