Not having huge variations in uniforms for team sports seems to make some sense to me (you can't have everyone wearing a different color...) for something like tennis or chess I can't see how it matters much.

All the other bluster about tradition and standards or whatever else is all just covering fire to exclusionary policy. Whether that be race based, gender based, class based or otherwise, it's a basis for excluding or removing those outside your group who can't or won't bend to your requirements.

The one and only exception I know of to this is safety dress codes, like loose long hair or garments around certain machinery that could catch those. The rest can go to hell.

If a White professional sumo wrestler insisted on Speedos or boardshorts as a protest against discriminatory Japanese garb, would he be a freedom fighter, in your view? A disrespectful buffoon in mine.

May I suggest you visit Wikipedia maybe?

Some weddings are explicit, sure. And that's a couple's choice, to exclude some of their friends and family.