No doubt this contributes to it ... especially from the woman's side of things.  On the man's side, it has to do with the fact that men have nothing deeper, more spiritual, more intellectual to guide and govern the appetites of their lower nature; those appetites themselves, of course, have always been there ... and so they have little to do with modern culture, but the lack of men's ability to guide and govern these appetites through their higher faculties, or even worse the conviction that these appetites need not and even, in some cases, should not be governed ... this latter is most certainly fruit of God-less modern society.

... but not godless.
(s.a. "Satanism". They are "governed" only to the extent that it promotes continued or expanded "power/freedom", with the end-state being the absolute expression, gratification, and exaltation of self. "... like God..." from a diabolic perspective.)

As an aside, the adjective "sexy" is quite ridiculous if you think about it.  It basically means "sex could break out at any time" like a flash-mob.  Or, "ready to have sex at a moment's notice--you never know when it will happen."

I'm quite curious to learn what source(s) you used for your definitions.  E.g., I strongly doubt that traditional textbooks on moral theology would discuss your subject matter using the phrase "flash-mob".  Or did you encounter the phrase during a critical review of "Francis" Bergoglio's "Amoris Laetitia"[‡]?

Comparing 2 U.S. "college" dictionaries 2 decades apart, I discovered that the earlier dictionary (ca. 1950), by a publisher synonymous with such works, seems to have no entry for "sexy", not even under some other head-word.  There were entries for enough closely related words that it seems highly unlikely to have been a matter of censorship.

Then after the "sɛҳuąƖ Revolution", as ascribed to the 1960s, was well underway:

sex·y (sek'sē) adj., [...]
1. Concerned predominately or excessively with sex: a sexy novel. 
2. (of a person) sɛҳuąƖly interesting or exciting; radiating sɛҳuąƖity. 
3. exciting or interesting: a sexy car.

Exercising the charity that's appropriate toward this site's owner-moderator, methinks he has, um, gone a wee bit wild with exaggeration.

Keeping in mind that sex is a small, small fraction of one's life [...] it's really stupid to describe people in those terms.

The word and its phrases are simply extremely subjective summaries of a person's visual appeal--and not much more, except for what they reveal about the viewer.  But I'd agree that the adjective is rather silly to describe an automotive vehicle.

-------
Note ‡: That's "critical review" in a sense soething like this: I'm determined not to be one of those people who vehemently criticizes a book or other docuмent that they haven't actually read, but why, oh, why, am I taking the time to read "Amoris Laetitia", when I have a Resistance chapel and a growing household to care for!?

May I suggest 'eaty' to address this major problem Matthew?
As in, 'guys, did you see the new girl in the queue at the cafeteria? She is soooo eaty!'

"Sexy make rapey..."

Yeah, while I don't believe in Evolution, devolution seems the new black.