IIRC you need to have a certain number of "real" fb friends (I'm assuming they judge this by connections to one another) to access it. A female friend of mine told me about it and showed me my ratings a few months ago. Cringeworthy.
And the worst part is you can't get your profile deleted. I've had several male friends personally email the founder and she won't delete ratings or profiles.
Your friends should create a similar app for men to rate women they've dated. Whether it gets accepted or rejected, it'll provide an interesting insight into the minds of feminists(anti-sexism, equality, true feminists. not women-are-better-than-men wannabes).