If I thought he was wearing his costume satirically, I might feel slightly differently. But as the theme of the party was "Colonials and Natives" which is clearly racist, that other guests thought it was funny to black up their faces, then I'm afraid I think it is more likely that he though a Nazi uniform would be pretty damn sexy. 20 is NOT that young. He is third in line to be our head of state. If he's truly that ignorant about history, then I think it is a perfect reason to abolish the whole idea of the monarchy. The whole family is tainted by far-right ideas anyway. Prince Phillip's sisters were, apparently, all married to high ups in the Nazi party. Edward VIII was a Nazi sympathiser etc. With that family background, you'd think anyone with any sensitivity at all would recoil from the swastika, not embrace it.