No one is a prude for not wanting to read certain material. Tell me I can't have something because you don't like it, and that's different.
I do think that Amazon's search system could be improved. If you type in "daddy", a lot of listings may well be results that the OP doesn't want. Smashwords has a "prude filter" to filter out erotica, that might be a good idea for Amazon to adopt. I've not seen any evidence that the existence of these books lead to people going out and doing these things in real life. They would have such fantasies even if the books didn't exist: non-readers and those in illiterate societies aren't any less likely to have such fantasies.
Even putting aside content that some might find objectionable, so many of the results are irrelevant. In a bookstore, I wander the shelves by category. One minute, I might be in the mystery section, the next, I might be in the science fiction section. I don't want all of fiction in one section, let alone all books in one giant section. Let me search in the Kindle Store by category.