Some people like boobs, others like ass, and a subsection of people just love feet. I guess if you really think about it, adoring any body part is a “fetish”. It’s just socially acceptable to like tits or ass, and society has deemed adoration of feet as undesirable.
Adoring the reproductive parts of our bodies seems like a normal biological response though being so fascinated by them that you would be a a contributor to WikiButt or whatever would also be strange to me. To fetishize the foot is something different.
I would think things that signal healthiness or contributors to increased chances of survival are subject to a biological response, rather than specifically reproductive parts. In which case, a foot devoid of issues can be a pretty big signal of healthiness, for example one not subject to bunions or flat footedness, etc.