I believe every man and woman has either read about or heard this phrase been spoken at least once in their lifetime. Besides the obvious connotation ascribing men to pigs, what is the reasoning behind the phrase and how did it originate?
I googled it but didn't find much besides this About.com article on Male Chauvinist Pig and an entry in the venerable Urban Dictionary.
I also did a case-insensitive Google Ngram search and came up with this:
It shows that the phrase was been rising in popularity since the 1980s.
Best Answer
The oldest explicit association of men (males) with swine that continues to be widely recalled today is the episode in Homer's Odyssey in which the enchantress/goddess Circe transforms most members of Odysseus's crew into pigs after they gorge themselves on a feast that she prepares for them. So the first memorable instance of "men are pigs" involved men who had literally (and literarily) become pigs.
As for the English-language expressions "men are pigs" and "men are swine," a Google Books search suggests that the latter phrase may have appeared first.
Men as swine before holy things
One early instance appears in an 1843 translation of The Homilies of St. John Chrysostom, Archbishop of Constantinople, on the Gospel of St. Matthew (written by the year 397), who softens the blow a bit by indicating that only a certain subset of men—"them that abideth continually in an unchaste life"—are swine:
This is all a gloss on Matthew 7.6, where Jesus says (in the King James translation):
That, too, is a fairly strong expression of the idea that (some) men are swine. Moving now to the proposition that all men are swine, we have this comment from Thomas Birks, First Principles of Moral Science: A Course of Lectures (1873):
And Stanton Coit, in The Conservator (November 1894), asks
Men as pigs in their relations to women
The phenomenon of men being equated with pigs as seen through the eyes of women seems to have taken hold very early in the twentieth century. From Julien Gordon, "Lady Star's Apotheosis," in The Smart Set (February 1901):
From Barry Pain, Lindley Kays (1904):
From Edwin Pugh, Peter Vandy: A Biography in Outline (1909) [combined snippets]:
From Anna Costantini, Ragna: A Novel (1910):
From A.A. Milne, "Once a Week," in Punch, volume 143 (1912) [combined snippets]:
And from Cyril Harcourt, First Cousin to a Dream (1914):
So before the Great War was well under way, the question of whether men were, in general or only in some permutations, pigs with regard to women had arisen more than a few times. I note that five of the six authors cited above were men. Perhaps they intended their salvos regarding masculine swinishness as preemptive strikes to ward off criticism by actual women. If so, it didn't work.