The clinical sounding thing doesn't actually sound quite right to me. "Kink" for me includes things that cause arousal for other reasons that aren't necessarily that. For example I have kinks that have absolutely nothing to do with penetration or even being in the context of any sort of sexual activity. They're just things I like in that way.
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.
If squares can be rectangles, rectangles can be squares, by virtue of happening to be a square that is also a rectangle. However not all rectangles are squares.
I suppose I get the point you're trying to make, but the bar of exactly what makes something a kink or not is something I don't really understand.
