I definitely agree that if something is on show a lot, people will become desensitized for it, just like sex and violence on games, movies and porn. I actually think it’s a good thing that nipples still have an effect and aren’t just made out to be just like any other part of flesh.
If you are interested, I wrote about the topic two years ago:
https://steemit.com/photography/@eveuncovered/to-free-the-nipple-or-not-to-free-the-nipple