I’ve heard the socioeconomic differences thing many, many times, and have kids that wear uniform. But I’ve never understood that argument.
It conceals socioeconomic differences. Which in the case of economic differences, is probably not egalitarian, strictly speaking? Ditto for social “class” in the sense of whether the family is historically “monied” and has particular dress style. In the case of cultural or ethnic differences, I do not see how the egalitarian logic follows either, as freely expressing your identity is restrained.
In terms of bullying… in my experience bullies will always bully. They will just do it on your overcoat, or how old your uniform is, or your earrings, or your accent, or the colour of your hair. I don’t know, maybe the uniform helps a bit…
I found this: https://www.nationaldaycalendar.com/april/scottish-american-heritage-month-april without too much difficulty.
Not sure if there is an English or Welsh version, or British. There may well be local ones…