If you're ignoring the giant societal can of worms, you're not getting a good understanding of the situation. In the 2010s the zeitgeist was that they were too prudish, and Instagram in particular faced a number of controversies for taking down topless photos that the subject of the photo felt should have been allowed. I guarantee that, for almost every piece of sexual content you've seen on Meta platforms, there's a large and passionate group of people who believe that it's perfectly acceptable and any reasonable social media platform should allow it.