My point is people everywhere have about the same morality level, i.e., Americans are no better than Chinese. But it is the government system that makes a huge difference.

If you think "Americans probably are among those who tried harder", it is because of their better system, not because they are American. :-)

On the other hand, even with this better system, people's "evil" (sorry, I have to use this spiritual word here) side would still cause a lot of problems, e.g., a few low ranking military personnels were used to cover something up.