It’s absolutely true, because when they grow up they may be the ones that cling to the first man or woman, that tells them they’re gorgeous, and then lets that person treat them however they want.
Tell them they’re beautiful, so they can be confident in themselves, and know they deserve greatness, they’ll have goals and work to achieve them. Little girls are all beautiful, maybe not in our “standard” of beauty in America, but they all have beauty and potential.
Little boys are handsome - but they world caters to their achievements anyway. Girls, they’re going to have to fight tooth and nail to be something - and they’ll earn that shit.