Spotting the "Hoo-Hoo"

Phallic symbols are used all over. They're usually a sign of power and dominance. Other times just for kitsch(weird how a penis can be a symbol of power or something humorous). But the use of vaginal imagery in ads seems much less commonplace.

I came across an article called Spot the Hoo-Hoo. Most are obviously directed at women. Few towards both sexes.
Here are two examples of ads directed at women. The left, Dior lipstick, and the right, a womens magazine. The images here are symbols of feminine beauty and interest.


The ads below are for womens health. The ad to the left is for pro-choice/anti-abortion and the ad to the right is an ad against rape/violence towards women. They use the subtle image of the female anatomy to represent women's strength in facing issues.


Why is it then that hinting at masculinity makes a product accessible to both men and women, but femininity only seems to be marketable to women?