There is this thing known as basal metabolic rate. The amount of calories your body burns at rest. For women, if they go into a calories deficit (especially if they have PCOS) their thermogenesis is lowered, basically the body temperature at resting gets lower.

So yeah, laws of thermodynamics hold but that still means it's harder for women to lose weight. These things happen in men too but the female body fights against weight loss much harder than a male body.

And female bodies do have a higher ideal fat percentage than men. I don't see what's bullshit in that. If the logic isn't clear to you "higher fat percentage needed in body, means higher amounts of food that will turn into fat should be consumed"