I'll never get it

I took Kate to Walmart the other day dressed like this and I had a very sweet and cute old lady come up to me and ask how old my son was.

Now I have to ask my self at what point would a mother of a boy ever put her son in a pink shirt that says "daddy's little girl" on it?!!! Isn't a little girl allowed to not wear pigtails, dresses and bows at least once a week and not be called a boy? Seriously!!