Can Riker legally stop Ro Laren from wearing an earring?

One of the most upsetting moments, for me, in Star Trek, is in the episode ‘Ensign Ro’ (TNG, 5:3), when one of the most decent characters in Trek, William T. Riker, does something really terrible. He directs the eponymous Ensign to remove her Bajoran earring. As any watcher of DS9 knows, the earring is a religious accessory of profound spiritual significance, a mark of being part of the faith of the Prophets. Star Trek, of course, believes in IDIC—infinite diversity in infinite combinations. How could Riker be so terrible as to declare that, on the Enterprise, an ensign was not permitted to wear a religious item?