I think that's one of the points of the article, or at least an observation. Bodybuilding made her more attractive to men, then as she excelled, made her much less attractive to them. The world changed around her as she changed appearance, as men held open the door for her or ignored her, corresponding to her attractiveness. Bodybuilding for women was for years obsessed with making sure the competitors preserved their femininity, as if building too much muscle takes that away from a women. One of her idol (Bev Francis)'s major contributions to the field were ignored by the gym friend, because he viewed Francis as being too unattractive to have sex with, and that was all he cared about.
Beyond that, I think it's extraordinarily hard to not care what strangers think of you. Not a particular stranger, but just strangers as a whole. Depending on where you live (e.g.catcalling is more common in particular cultures or more metro areas), you can have people commenting on your appearance every day. After years of that, of course you start noticing the comments being more or less nice, or more or less frequent, and I imagine it's easy to obsess over it. It should be pointed out though that it's clear the author doesn't enjoy obsessing over how men think of her - I imagine these are more intrusive thoughts.
I enjoyed a feminist lit book with similar themes of a character who embraced being 'unf*ckable' called "Dietland". The 2nd half of the book goes off the rails but the first half was thought-provoking to me, for anyone who might be interested.