I think that the Chinese government example is extreme. It is stupid, but harmless. The government's job is not to legislate morality, but it does need to be done in some cases. For instance, some people think that there is nothing morally wrong with having sex with minors, so that definitely needs to be legislated.
While I don't believe governments should regulate normal behavior, I'm inclined to think that the case in China of people eating bananas seductively could be a crack down on lewd behavior being published on social media. While the act of eating a banana is not questionable or criminal, certain actions or scenarios could be interpreted as sexual in manner. This may need to be regulated if it is in fact the case.
While I can understand China's banning live streams of people eating bananas seductively, I feel this law is taking the issue way too far. Of course we know what the participants in the live streams have in mind in their performance but at the heart of the matter, someone eating a banana is just that-> someone eating a banana.
No, a government should not legislate moral behavior because who defines morality? If the far right in the US defined morality, most basic curse words would be banned from all television shows, no matter what hour they were on TV. The far left would have a far different view. Therefore, who is to decide?