If you accept the institution of a monarchy then you are buying into and endorsing the idea that some people in society are more privileged than others and have a right to exercise that privilage, therfore you are being hypocritical if you then condone the actions of two privileged people when they act upon that privilege. You can’t have it both ways, you either think that some are better than others and deserve special treatment, or you belive everyone is equal and deserves to be treated thusly.