I kinda have a guess on why this often affects female characters rather than male ones (with certain exceptions, like Wesley Crusher). It's because women are more likely to insert themselves in stories. For what I've seen myself, boys want to be Batman or Superman, while girls want to be Batman's girlfriend. I definitely need to read more about this, but I think that's basically the problem. Now, these girls who have been receiving constant feminist propaganda dont' want to be Batman's gf, but his aid or the ones that simply solves all his problems and save the day, but the feeling behind it it's the same. They portray THEMSELVES in the story, while boys want to be the archetype. If I had the chance, I'd like to ask Peterson about this question.