I like to stop by the international grocery store from time to time and when my wife sees a Yorkie bar with "It's not for girls" printed on the wrapper, she gets pissed off, buys a few and eats them out of spite. If the wrapper said something like, "Girls love them!" she wouldn't even glance in their direction (and yes she also drinks Dr. Pepper 10).
The ad agency that came up with this must be located in the midwest. That's the only part of the country I know of where this kind of misogyny is still considered amusing.