I don’t really know why spooky times equal sexy times, but they do. In point of fact, they have since mid-12th century Venice, with the origins of the Venice Carnival. And, by the 18th century, the phenomenon had truly reached a point of debauchery and sexual “excess” as it spread across Europe.
But, the reasons for spooky times oft becoming sexy times is not such a pressing concern as to force one to go into a lot of research. We only need to enjoy it for what it is. 😛