There's always an option to enforce requirement of such features using the legal system.
If laws can and are (ab)used by governments and their TLAs to legally force equipment vendors and service providers to create various surveillance features and misfeatures (backdoors, security strength limitations), it's only reasonable that they must be used to create privacy-enhancing features for the public good, too.
The main problem is that somewhere some database will hold the information about citizens and a "likesPorn" flag. That information is personal. Alcohol and cigarettes both have age limits, but there is no database that people need to register into ("wantsBooz = TRUE") before being able to purchase their first drink.
The adolescents teaching each other how to get around filters - that is exactly what ends up happening. A few years back, Turkey had a pretty long ban on Youtube. Countless sites for tweaking browser settings specifically geared for Turkish Youtubers emerged. There was even a cartoon by a prominent artist that depicted the PM declaring his agenda: "We won't lift the ban until we have 70 million DNS experts."
But yes, this apprehension of nudity is something I've always found so bizarre. Why is seeing skin of our species such a big deal? At what point of our social evolution did it evolve that way (because the idea of clothing is pretty universal to humans).
The idea of clothing isn't quite universal, but nearly so. Still, we're something of an outlier in how serious our nudity taboo is. As far as I can tell most cultures are ok with women going around topless and most think that it's ok for men and women to see each other naked when bathing, though I guess Hollywood is changing that.
