I know what you mean, I bought some cheap knickers for potty training my minded children from Primark. They are absolutely inappropriate, little girls sit with their legs apart and all you could see was their 'bits'
I took them back and they refused a refund, I told them that they were sexualising little girls have crotches less than an inch wide, bearing in mind these were for 2 year olds.
They could the supervisor who asked what the problem was, I explained and she said no refunds son personal items. I told her in a very loud vice in a queue of about 10 people that exposing a child's genitals and being able to see all of their labia was not appropriate and that I would write to the press about it.
She rapidly gave me a refund!
The only lovely knickers I have found, and also used for my own DD are Petit Bateau, they come at a price, but are beautiful and cover all up to the waist!
petit bateau
You can get them at John lewis, Selfridges, harrods etc, they last for ever and stay soft.