I think at least part of it is a backlash against the proliferation of pornography (its shocking just how prolific and how degrading porn actually is compared to the ‘good ‘ol days’). A lot of youngsters were first confronted with porn as children through their smartphones.
But a lot of it also has to do with changing attitudes towards woman and sexuality. We’ve had corporations marketing woman and teen girls as sex objects for decades now, but we now also have an increase of violence against woman and we have the manosphere and far-right extremists campaigning against basic woman’s rights like abortion, equal pay and whatnot.
So I guess the real question is, are more people taking offense of nudity because of their conservative beliefs? Or are more people viewing nudity in popular media as a means of sexualizing (and thus degrading) women?