I really don’t know.
The most common explanation given is that by banning all sex and violence from entertainment, that keeps Chinese society stable and safe and lowers the crime rate and thats why China is so safe.
But is that really the reason? Or is it more culture-related? Let’s look at the world map here
We can see from the statistics here that the violent crime rate does not seem to be related to whether a country has sex/violence banned in entertainment or not – Japan in fact has the world’s lowest violent crime rate and it even has legal pornography!
You can see that violent crime is first and foremost related to the economy – poor economic countries tend to have higher crime rates.
A lot of the safer countries – Canada, most of Europe, Australia, Korea, Japan – have rating systems for their entertainment and sex/violence in entertainment is not banned merely restricted.
So I am not totally sure why the CCP thinks censoring ALL sex/violence in entertainment is a good idea because like the link says – it hurts their entertainment industry and their ability to export their movies or games. Japan meanwhile – the largest video game exporting country in the world. Wonder why that is. Could it be because of all the sexy characters?