Though I don't agree with what they were saying, I suppose those ladies have a right to say that
in private, but certainly not in front of you and your little girl. Saying that with you there basically is implying that you are messing up your daughter's life and turning her into a spoiled brat by buying her a cute little pair of sandals.
I don't see anything wrong with little girls liking pink and princesses. For a long time, before the mass production of disney princess merchandise and even the movies, girls have been known for wanting to be a prrincess, I know I sure did. Would they be mad because all of the sports products (clothing, toys) available to boys because "they're creating unrealistic dreams of them becoming a professional athletes"?
The only conclusion I can come to at why they would be compelled to say such is maybe because they're jealous they did not have princess toys when they were young, once again I'm not not sure. It's very rare that you hear a woman complain about pink, I never outgrew pink (though I have matured up to my favorite color being turquoise, still pink isn't far behind), my bathroom's pink, I just plan on painting it beige when we move!
By the way, when my DD13 was 2 or 3 she was wearing a Barbie t-shirt one day when I was at the dentist and the receptionist had to make some rude comment about Barbie, I'm sure puposefully after she saw my daughter!