But I am not talking about prejudice at all, or refusing informal types of leadership by qualified and competent people. I'm not saying the Noldor despise Tuor or Turin or Celeborn or Earwen. Tuor can be informal military leader but we aren't asking why a human was not elected High King of the Noldor. I am talking about a ceremonial title that has rules associated with it. Yes, I am certain that if Finwe is King then his wife is Queen. All the Eldar considered Queen a title of great importance, because the Queen (or otherwise the highest-ranking royal or noble lady) is Mesanie/Besain, the keeper of the sacred Corn of Yavanna and baker of the sacred lembas. That is a very high and important position, an irreplaceable position.
A male elf must never, ever take any part in sowing or tending or harvesting the Corn of Yavanna, nor any part in baking or storing or bestowing the lembas. All of that was very strictly reserved to the women alone. Does that mean that the Eldar look down on men and are sexist? No, it doesn't. It means that they have strict gender roles and ceremonies/rituals.
A non-ruling King is not as important as a Queen-Mesanie because he can have no part in the lembas rituals, but I think it still is a plausible concept for the Noldor to consider it a significant position.
Yes, Earwen is now the Queen of Tirion. But the Valar decreed it, so nobody is going to argue against it.
Keep in mind that the Noldor also determined pretty early on that the Edain needed to have their own human rulers instead of being ruled over directly by Noldorin kings. The Noldor didn't decide that out of prejudice against themselves, nor was it because the Edain were prejudiced against the Noldor. The Noldor thought it was more proper for each group to be ruled by one of their own people.
Queen and King have very different significance in Numenorean society and I don't think it makes sense to compare the two. The Numenorean King or Ruling Queen is the High Priest of Eru, but has nothing to do with the Corn of Yavanna, and at first had nothing to do with warfare. The whole structure of Numenorean society is pretty different, as are their royal inheritance customs (to the degree they make codified, written laws about it.) I think comparing Elves to medieval Europeans is even less relevant, especially since class and religion were so much more important to European royal marriages than ethnicity, but the Noldor don't care at all what class Nerdanel or Anaire were. Elves aren't Humans.