Fun on Amazon

Amazon.com gives you recommendations based on your browsing history. Today, there are two books in my browsing history: Angela Brintlinger (ed.) Madness and the Mad in Russian History and Culture; and Laurie Manchester, Holy Fathers, Secular Sons: Clergy, Intelligentsia, and the Modern Self in Revolutionary Russia.
So far, so dull, right? But what does Amazon.com recommend on the basis of me having looked up these two books? "Clergy Priest costume" - at a mere $20, or better still, "One Bad Habit: Sexy and Fun Womens Nun Costume".
I'm sure there is a perfectly reasonable explanation for why both of these are only available in Small.