Score

Why are so many women who are wearing red shoes knock-knee-ed and pigeon-toed?

That's a very good question. Others have wondered, too. See also my friend Holly's list: Legs Turned Inwards, Red Shoes. I borrowed half of her idea because I knew there were some covers with red shoes that weren't worn in this awkward stance.
Maybe red shoes warp your balance. Or maybe these women wear them to distract from their knocked knees and pigeon toes.

It might be due to an internal quarrel about the significance of red shoes. Red, especially as depicted on these covers, is a powerful choice of color for shoes. It seems to say, "I can make strong choices". But to counter that bold statement and still keep these women/girls "in their places", they have to present them in the awkward or subservient pose.

Notice: the single red shoe alone on the cover seems much stronger. It seems to say, "I am determined and ready, all by myself." Even some of the titles associated with this stance seem to imply power and determination.

Yes, I had that thought too. "Don't be intimidated by my bold choice of footwear--I'm still adorably awkward and clumsy!" Good observation.