Questions

Think about it. Compare the beauty of your conventional boy/man and your conventional girl/woman. The Mr average I post below is more on the "not that ugly" side if I say so generously:

Now. The girls & women can take this to another level with their beautifications and look like this. Men and boys can not. This super pretty one resembles in some ways the pink haired cat girl.

Boys & Men have very limited choices to be eye candy. They can either go for a look for someone like the Serious Sam guy or they can turn into transgirls and follow the beauty ways of girls & women.

And we've not yet covered the ugliness of the average boys/men such as geeky dorks, nerds, who look like moles with their glasses and those, that can't make use of most of the beautification things of girls without looking like an obvious man trying to imitate as a woman.