What's wrong with sexually explicit content? Is Google controlled by Taliban or something?
The only "banned books" lists apply to school libraries/librarians.
I cannot possibly see what the justification would be for such a law. It's just words. It is no different than saying 'fuck' in front of a minor. It is clearly protected speech.
[0] https://news.ycombinator.com/item?id=9098875 ("Google bans 'explicit' adult content from Blogger blogs", 2015)
- "Until today, Google's Blogger platform previously allowed "images or videos that contain nudity or sexual activity," and stated that "Censoring this content is contrary to a service that bases itself on freedom of expression."
[1] https://news.ycombinator.com/item?id=18590944 ("Tumblr will ban all adult content on December 17th", 2018; 464 comments)