You've written to the gym! 
Brilliant. What did you say? That they should have overweight unattractive people handing out flyers - for the gym, a place where people go to improve their bodies and aspire to the perfection - oops sorry, falseness?! of the people advertising.
And I have to disagree on the idea of a 'good' body being subjective. In our society at least: youth, slimness, defined boobs and bum, long legs in relation to body, toned limbs, clear skin, small facial features with big eyes and lips, long thick shiny hair. If I saw a woman with all of these features I would stare. Actually I did in the pub DH and I had lunch in today, our waitress was stunningly beautiful. I laughed when I saw DH looking at her slightly agape, it was total instinct!
I don't understand why it bothers you so much. It's not a feminism issue for you, it seems to be just that the near naked female form offends you, and you are keen to insult the women involved, first calling them 'whores' now claiming that all their perceived beauty is 'false'. It really does seem like jealousy tbh... are you hoping they will employ you instead?