i don’t think the point is that dunk should have singlehandedly overthrown the monarchy it’s that being complicit in violence against women is an inherent part of a patriarchal institution like the kingsguard and the moral character of individual members cannot overcome it.
Sorry but realistically what could dunk have done as captain of the kingsguard to stop Aerys and Rhaella from getting married lol even if he floats the idea to egg, Egg is still the king