At least since the days when cable and satellite networks appeared, there has been way too much media to watch and listen to. And from a former radio listener, if you were in Los Angeles, it was always true. Dozens of radio stations playing various formats and various musical styles ... most playing around the clock.
> In the US a woman shaving her head meant she was borderline insane
I didn't see the movie, but in real life, even though it was rare, I never knew anyone to express such thoughts. I'm culturally US, I guess, but not as media-connected as many seem to be. That said, I never heard or thought such a thing until you wrote it.
Maybe it is something like Mastodon users nagging newbies about "Fediverse etiquette", as though their imported Twitter and Tumblr based etiquette didn't violate pre-existing Fediverse etiquette when they came.