I am soo mad (gender roles)

I work in a supermarket and today a little boy and his grandma were doing groceries. The grandmother let the son pick out a small book to take home. The little boy ran to the checkout with Dora Princess Adventures to which the grandmother replied: 'You are not a girl'. She refused to pay for the book because of she believes only girls can read that. The boy were very sad, because he didn't get the book he truly wanted.

I hate narrow minded people who think a Dora Princess book is only for girls! And the way she said it to the boy: "You're supposed to be a man, not a sissy." Ugh. If the boy wants to read about princesses, let him read about princesses!