Kinks and sexual preferences both include things that don't directly relate to sex. Not sure if this helps to clarify, but all kinks are sexual preferences but

Kinks and sexual preferences both include things that don't directly relate to sex. Not sure if this helps to clarify, but all kinks are sexual preferences but not all sexual preferences are kinks. Kind of like how all squares fit the classification of rectangles but rectangles are never squares by definition. As far as I can tell it is mostly about what is common and expected vs less common and less expected. It's not the most important distinction in the world IMO in common conversation. To social scientists and such like the author it is of course a fascinating distinction to dig into.