You're framing of "sex icky" is a common reductionist approach to remove all humanity from the topic and try and make it purely logical. But that's always been a ridiculous way to argue.

The human experience has never been pure reason. A picture of a naked person will have wildly different effects than a picture of a dog, even though you could technically say they're both "just pixels on a screen". Reductionism doesn't get an argument anywhere; it's too commonly an intellectually lazy defense of the vulgar.