If you are a man of a certain age, you probably find the sight of your wife in her brassiere...thrilling beyond words. It has everything to do with Pavlovian conditioning.
I pity the poor young men of today. Too much explicit video.
And now Covid-19. Everybody is walking around in public wearing half a brassiere over their face. What emotions will the sight of a bra trigger in the young men of today? A frantic need to search for hand-sanitizer? A desire to count rolls of toilet paper?
On a related note: Media reports that men ages 19-through-34 report far less "sex with a partner(!!!!)" than past data.
One must wonder if they would get the same results if they segregated the respondents by married and unmarried men.
Sometimes data that appears to hold a tectonic shift is deeply confounded by other factors.