It's understandable that we define asexuality through absence; we mostly or entirely lack a sense of sexual attraction, therefore we are asexual. However, I think another useful way to define asexuality for some of us on its spectrum would be as a fundamental difference between what society believes is sexual and what we enjoy.
A commonality I've noticed among some ace-spec people, myself included, is that some of us do have a defined sense of erotic attraction through kink, but that little to none of what we're into is actually considered sex. My kinks aren't something to make sex more exciting, rather they are the entirety of what I find erotic. Sex is not really part of the equation.
The reason I've gone back and forth for so many years on whether or not I want to identify as ace despite, y'know, not finding sex erotic or ever enjoyable to think about, is that the "aceness as absence" model didn't feel applicable. I didn't feel like I was lacking a sense of attraction. In fact, I could confidently identify that I am a lesbian and that there are things I find erotic. But I identify as grey ace now specifically because my sense of erotic attraction isn't sexual in any conventional sense.
This isn't a new conversation in ace community spaces. It's a huge reason we define asexuality as a spectrum. However, I've never seen the point phrased in quite this way? So I wanted to make this post because, if this framing is what made things click in my own head, maybe it'll be useful to other people, too.