I understand that Amazon has to cater to all tastes, within reason, but there should be some separation of the 'adult' material from the rest of the catalog.
My beef is that I write bedtime stories. A search of 'bedtime stories' at Amazon will throw up children's bedtime stories and a awful lot of erotica, including s/m (by which time I feel like throwing up).
n:
In a nutshell, I think that customers should have to explicitly enable adult material in their search preferences.