The reason for "girly girls" is to split off young females from the old, gray, sexless, obsolete ones. When they do this they can call themselves "radical feminists" since they have no idea what it is. So, "femininity" is power, the power of sex appeal, and politics is a bore--and threatening to boot. It's an effective divide-and-conquer strategy employed by the male media. It always works like a charm--except in the early 1970s, perhaps.