Just answer the questions in sequence.
Well, the answer to the last one is that you don't need to know everything about sex in order to desire it. People can, for example, get horny without knowing the definition of maschalagnia. In fact, that would be most people.
And the same goes for pretty much everyone else. Of the people who desire (for example) to eat a pineapple, only a tiny insignificant fraction know that they don't grow on trees. But they can still desire pineapples, they don't need to know all about them to do so.
And knowledge of good and evil doesn't seem to have any sort of privileged status in this consideration. Perhaps pineapples are grown by slave workers and watered with the tears of orphans; or perhaps, on the contrary, all profits from the sale of pineapples go to charity. I have no idea, but I still always know whether or not I want to eat a pineapple.
Edited by Dr Adequate, : No reason given.