I'd have hated this. I always wear a dress or a skirt. I don't like trousers particularly. As a teen I wore jeans but these days that's a rarity. I found a dress and tights way more comfortable. And in the wet or snow I hate trousers when they get soggy on the ends!
If a school is having an issue then they should just have a list of options: trousers, shirts, skirt of set styles and then say any child can wear any of these items.
Or if uniform is becoming a massive issue, scrap it and introduce a general dress code for all pupils.
No reason why skirts should be banned at all.
Most reasons given seem to be about boys - either because they want to wear them, or because they can't behave towards girls who are wearing them (staring at girls legs, upskirting) - neither reason is the fault of the girls; address the boys behaviour (let them wear them too; discipline inappropriate or bad behaviour) instead. Don't lay the guilt or blame on the girls.