This and a couple other comments in this thread point to an aspect of Star Trek’s world building that hasn’t sat right with me for a long time. It’s supposed to be an utopianistic, egalitarian future. There’s no scarcity or need on Earth so everyone is supposed to be here because they want to be, out of a love of exploration and scientific advancement. So why is there such a disparity in treatment based on rank? Why does an ensign get stuck with a bunk in a hallway while Captain Picard gets a cushy executive suite? O'Brien at least had real quarters to raise his family in, but they were a comparative closet next to the bachelor Captain's. Doesn't seem right to me.
All to say that, in my mind, if an ensign needs to stick to a manner of dress, so should an officer of rank. They're all part of the same fleet and deserving of the same respect.
Who says they aren’t to code? Maybe they are allowed to implement accents from their native cultures? I mean we are talking about the “woke” starfleet here.
In Worf's case, that is actually true. His sash is a culturally significant item for Klingons, displaying his house sigil for example. The same is true for Ro's earrings though. And since Worf got an allowance, Ro should get it, too (which Picard eventually grants. But Worf never got that remark from Riker).
Deanna however just wears civil garments.
There also was a bunch of selectivisim going on: by allowing the only klingon in Starfleet, a son of a major house, wearing the sash, and then having him posted prominently on board the bridge of their flagship, was a power move.
I could see Tori being allowed to wear more casual attire as a way to help put the crew at ease during sessions. But as a bridge officer and member of senior staff, yeah she should be in uniform
In the US Army Sikh soldiers can wear their turbans, beards, and kirpan due to those things being part of their religious beliefs. The soldier does have to get permission and a uniform waiver first but that's never an issue.
I would bet Laren's earring is the same type of thing. She's a contrarian so she probably just never put in the paperwork to get a uniform chit allowing her to wear her earring and the others did.
I can't blame Tom Riker. He must have had a serious identity crisis on top of feeling that his promotion and life were robbed from him. I'd be bitter too.