Why is it that very few girls and women admit to being visually stimulated when seeing a half-naked or naked guy?

Here's a thought. Maybe it is a question that should not be asked in the first place. I know some will disagree and there are exceptions to everything but in my experience females are more modest than males and are reluctant to discuss or admit to such things.

Because women need touch and romance in order to get turned on. Some women can get turned on by guys dancing and stripping but many cannot and need more than that to get sexually aroused. It's the way women are wired and their hormones compared to men that make them this way.

Because they're not. The male form is pretty ugly, to be honest, women are more evolved than men, so they look beyond some flab and dangly bits