And didn't Riker or Picard give Ro some crap about her earring, which is a part of her culture and religious upbringing.
It was Riker. And I think it was a case of Riker not really knowing what the ear piece meant, he thought it was simply a piece of Jewelry and not a religious symbol. When Ro put it back on in front of the more knowledgeable Picard, he didn't have a problem with it. There was a Bajorian with the ear piece in First Contact. And there was a Hindu in TOS with a bindi.
... the reason it wasn't prosecuted as murder was ...
It wasn't murder, it was a mutually consented to duel to the death. Conducted in a territory where such was authorized and legal. Definitely not murder.