I really don't think girls are socialised into it, I think some girls genuinely have a love of playing with clothes and having fun with them, an expression of who they are. My DD has always been like that, she was obsessed with fairies as a young girl, pre-school age she only really liked wearing her fairy costume. She loves jewellery and at her Grandma's house would sit for a long time trying on all of my MILs bohemian jewellery and beads, none of it was pink or princess like. She enjoyed fairy tales and still enjoys fantasy dramas. She's nearly 13 and loves clothes, jewellery, eye makeup up in particular, trying stuff out, she sketches designs as she wants to be a fashion designer, she buys bits from Vinted, bags, tops, jewellery as she has a passion for this. I was similar as a child and was definitely not brought up as a princess, my Dad was heavily involved in politics and current affairs and discussing these things with us, even when we were probably too young but I still much preferred retreating to my flower fairy books or Narnia and dressing up and pretending to live in mythical worlds!
I get frustrated with this line of thought as it suggests there is something wrong with anything other than the practical or sporty with girls, when that isn't the case. I would prefer no uniform but yes my DD does sometimes have the short tartan skirt on as uniform, with DM boots and jewellery she can get away with. Sometimes, she also does wear baggy black trousers for school. When she was at infant and Junior school she at first wanted to wear a pinafore dress but underneath she wouldn't accept the boring airtex and I ended buying her a dolly collar style white long sleeve top from Jo Jo Mamen Bebe, she hated reception year precisely because she could no longer go to school in her fairy dress.