Maybe they realize it's a personal waste of time. Obviously wikipedia does great good for society. But making sure an article on wikipedia is correct ranks pretty low on the hierarchy of one's needs in life.

Maybe it's just my personal experiences but I've found women to have a better grasp on what's important and not important to their own life. They have more perspective, if that makes sense. Men on the other hand will kill themselves trying to win an argument and forget their whole lives while doing it.