I think it would be more accurate to say fat women are less attractive on average to men. Almost any woman that isn’t literally disfigured can find some guy willing to have sex with her, but the quality may be substandard. While the odds may be good, the goods are odd. I don’t think it is helpful to say men are willing to have sex with fat women, because men are willing to have sex with a lot of thing under a lot of adverse conditions, and they are additionally willing to delude themselves into thinking what they are having sex with is highly attractive to them. As a woman, saying men are willing to have sex with you is a very low bar indeed.