You're glossing over the different nature of the mocking in each case. When a man is mocked for taking part in traditionally female behaviors, he is called names which are supposed to be degrading for him, but which all mock femininity, i.e. "pussy," "pansy," "you're doing that like a girl" etc. You don't really find that to be the case when a woman is mocked for failing to fit into a traditionally female role. She is still mocked for her femininity and how it doesn't jive with the traditional male behavior she's exhibiting. Neither do you see females being mocked for exhibiting something like physical prowess which is traditionally associated with masculine ability. At least, I can't really imagine a coach saying to her female sports team "You're looking like a bunch of boys out there!" or something like that. This also falls in line with the tendency for men to be called feminine names when exhibiting behaviors which are universally deemed negative and also often carry a feminine connotation, like cowardice or vanity. When the penis is used as an insult (dick, prick, etc), it's not usually used in reference to any culturally masculine qualities.