She shouted/was horrendously rude because she was embarrassed, knew she was in the wrong for not having the dogs on leads, for preventing them from rushing your poor daughter (I'm an adult, who has grown up with large breed dogs... and I would have been terrified to be rushed/surrounded by strange dogs!). That's all it (probably) was - and as another poster has said, she would have been nasty regardless of how you look, because some people just cover their being in the wrong and embarrassment at having it pointed out to them, by being foul mouthed/nasty idiots.
Not all dogs are prone to be vicious, and she may have been right in that they like small children, expected your daughter to be pleased to see them, and then became confused when she started to cry/get upset. But how are you, your husband, your daughter supposed to know that? They were strange dogs, you didn't know if they were going to attack any of you (not just your daughter) and they should have been under control of the two girls (presumably young women?) who were in charge of them at all times whether on, or off-lead.
I have a little dog who adores small children... but I don't let her run up to random children whom we don't know, because not everyone likes small, vibrating bundles of muscle and fur leaping around them, desperate for a fuss and a sneaky cuddle. She is trained enough to know what different whistles mean, and she obeys them. I call her back, hold onto her, allow the walking families to pass on by without having her try to join them... whilst she vibrates with silent desperation to be fussed over and petted by strangers. Why? Because I hope I'm a responsible enough dog owner, that I'm not one of those dog owners/walkers, and because I know that not everyone's a "dog person". My larger dog simply hides behind me if he sees a child whilst out ambling, because he's terrified of being randomly cuddled, hung onto, ears pulled by them. And I allow him to do that, because a frightened dog = a potentially dangerous dog.
A frightened child, on the other hand, doesn't have the same potential dangerous tools (teeth and very strong jaws...) that a dog does. You were in the right, absolutely, and the young women were in the wrong, completely.
I hope your daughter wasn't too traumatised by the situation, too. Please reassure her that it's okay to be wary of strange dogs, but that not every dog is irresponsibly owned. Some of us actually think forwards, rather than hope for the best whilst our dogs are off-lead.
Also, equally important, beauty truly comes from within. It doesn't matter what a person looks like, it matters how they are. I know a very beautiful young woman, who prides herself on how she looks... and she's nasty, calculating, manipulative, lies to get her own way, and doesn't give two shits about anyone but herself. You, I'm sure, are loving, kind, compassionate, and loved for who you are, not how you look. 