I would say that wealth inequality, lack of rule of law and most importantly; deep rooted and severe poverty are the biggest factors, more so than the offender's personal preferences. You tend to see the worst side of a nation's people when they have nothing. Hence, most parts of China aren't actually that bad in this respect, compared to many other poorer nations.

The countryside does have a lot of undereported problems, not due to censorship, but local culture. Victims are often blamed and potrayed as troublecausers, some many incidents will get brushed under the carpet. Also, the abusers are often powerful people that are either wealthy or in high level positions. If I recall, there was a particularly bad case in Hainan a few years back?