The somewhat licentious and 'Southern' (as Evola would say) nature of
this festival is probably attributable to the pre-Indo-European
Pelasgians--it predates the "ascendancy of Jove" (i.e. the
Hyperborean-Aryan battle-axe folk). Note the relatively 'lunar',
primitivist idea of the Golden Age here.
http://www.cs.utk.edu/~mclennan/BA/SF/MidWinter.html
"Ovid (267-302) says the Lupercalia is a rite of the Pelasgians (a
people "older than the Moon"), dating from the Golden Age before the
ascendancy of Jove; the naked ritual honors Pan:
The God Himself is wont to scamper high in mountains; He Himself
takes
swift to flight; the God Himself is nude, and bids His ministers go
nude, for clothes suit not a rapid race.
(Ovid, Fasti II.285-288)
In the glorious Golden Age all people went nude, living in grass
houses
and eating herbs, content to live on what they could gather without
agriculture or husbandry."