So France is starting an “experimental school uniform program” Sauce Do other countries also have that trend were conservative push for a school uniform rather than letting kids wear what they like ?
Then your schools are doing it wrong. Uniforms also typically come with a dress code that forbids excessive jewellery or accessories and they also mandate particular providers and exact material and specifications for the uniforms so there is no variation in material or other qualities.
Most of your points are just based on feelings and anecdotal experience that have no basis in reality when uniforms are properly implemented.