You hope the Federation is above respecting the cultural traditions and norms of other planetary systems, specifically, intermarriage of royals to maintain interplanetary peace? You would rather the Federatigon say "You go grrrllll" to little Elaan, possibly resulting in interstellar warfare and the deaths of billions of innocents?
Agreed. For anyone to argue for what boils down to a version on "identity politics" to take priority over the fate of worlds is...missing the bigger picture.
Perhaps the Federation shouldn't get involved in the slave trade? Stay out of it. Honour the PD for once.
I suspect Elaan is going to stab her new husband on her wedding night. I wonder how interplanetary relationships will go then?