I think the problem is hypocrisy. Writing how a guy gets brutally killed is ok. Writing how a guy had sex isn't. I'm exaggerating slightly, but the thought behind it is true. So I think this selective way of making rules, deciding what is 'harmful' has a connection to the rise of readers who don't want any romance.
The need for violence in entertainment could be linked to a need to release stress. The popularity of the face slapping the young master trope in CN WN could reflect growing resentment over wealth disparity. Where I’m from, there are even places where you can pay $50 just to smash things with a baseball bat.