Hmm...because having the flesh burned off your bones or dying slowly of long term radiation sickness etc. is a better option than being raped and bayonetted? Why don't we take a straw poll on that?
The allies had far less incidents of rape. And defently not systematic like Japan. If you really beliefe that its clear that you have never actually studied the issue.
Tens of thousands of japanese women were raped after ww2. The only reason that more japanese women weren't raped was because the japanese government provided "comfort women" for the allied troops.