I think the reason some children behave like this is because of poor parenting.
Sometimes children need help to know the right thing to do.
Those girls were discussing it in front of your daughter which was rude and unkind, and the consequence should have been explained to her as she is getting lifts and goes out with you regularly.
Sometimes parents leave their children down.
Years ago my 12 year old was invited to a birthday by a friend, 10 of them were invited.
At the end of the party as I was collecting her, there appeared to be upset and tears etc.
My daughter told me that 5 girls were staying on for a sleepover, and two girls were very upset not to make the cut.
Fortunately my daughter was very sanguine about it and not at all upset, but she said it was a pity as the whole party had been dominated by it.
There was huge upset apparently and the girls mum's were not impressed at all.
The birthday girls mum (she's very nice) rang me later to apologise if my daughter was upset too etc. and said what a bloody disaster.
I didn't sugar coat it, I laughingly asked her what was she thinking? and why was she surprised that it might sour it for a couple of the girls?
Did she not know how sensitive girls can be to hurt, and perceived exclusion?.
She invited the other 5 over the following weekend and it resolved itself, but she was scalded by the whole experience 😳🤣