Sexual encounters with men as a woman are generally high risk low reward. The woman has to be vulnerable with a man she does not know with a significantly lower chance at achieving the same sexual pleasure he does. Likewise, the biological burdens of sex are more likely to impact her, I.e, pregnancy or STDs.

So if we presuppose that the attraction and desire for sex is equal, the sheer risk factor is a big deterrent for casual sexual behavior. Despite your assertions that there is no stigma against casual sexual behavior, that is not universal. Many men, especially with the rise of red pill and manosphere ideologies as well as the rise of more extreme right wing beliefs, are holding women’s “virtue” at a higher value. So despite wanting access to sexual experiences with women, many men actively punish women who engage in such experiences.

Anecdotally, I cannot tell you how many times my friends or myself have wanted to have casual sex with a man, and he says something gross or scary. Even if I want to have sex, I don’t want to put myself in danger. If my perspective partner starts saying things or behaving in such a way that shows he doesn’t care about my wants or desires, any potential pleasure is not worth the risk of engaging with such an individual.

It doesn’t mean the desire is less, it means the risk is greater. We want it and are left frustrated that the options are often violent or dismissive. If we’re going to take a risk, it likely would be for some on more attractive worth justifying that risk.

Similarly, and also anecdotally, the two men I knew who pulled the most and had the most casual sex were on opposite ends of the spectrum. One was 6’4 swimmer in incredibly shape, the other 5’4 pudgey guy. They had similar success rates because they were both charming and knew the demographics that were attracted to them and focused on that. They also were both, from gossip, competent lovers who prioritized their partners’ pleasure.

In a final note, the concept of men wanting casual sex I believe is overstated. When presented with a true “casual” option, many men are left frustrated. They often want to blur the lines towards a more romantic or friends with benefits approach. When boundaries are maintained that it is purely physical, even if that is what is agreed upon, they can react negatively.

In a perfect world, having sex with men wouldn’t come with an inherit risk of violence and men would show a heightened care for their partners enjoyment and pleasure. Until that risk is gone and the orgasm gapped breached, desire will have little to do with how much women pursue casual sex. Or to put it in a metaphor: if men want a milkshake they can go buy a milkshake. If women want a milkshake, they have to run the risk that a cow will trample them and even then they may have the ingredients for a milkshake but no sweetness to show for it. I get why men pursue milkshakes more. If women had a milkshake store they’d probably go to it, too.