I think "you can't condition yourself" is pretty different from "intrinsic motivation is fixed".

Ozzy was used as an example in his essay. If you ask me, Ozzy is fascinated by gender because Ozzy is of atypical gender. Gender Studies majors are often gender atypical themselves, and I think it's fairly obvious that this something borne out of life experience.

I'm sure some things are fixed, but there are environmental features here that can be hacked. Ozzy might be physically predisposed to interest in a broad thing like "people's feelings" or something, but there is some sort of psychodynamic process routing this to gender specifically.

I think the right question to ask is "what is that process, and why is it so hard to trigger on purpose?".