We should note that Aharon was also punished for Merivah!
Let Aaron be gathered to his kin: he is not to enter the land that I have assigned to the Israelite people, because you[Moshe!] rejected My mouth about the Waters of Meribah. (N. 20:24)
But why is Aharon held responsible? The only part of the entire episode in which Aharon acted with Moshe is in falling on his face and fleeing from the people! Does this mean that the act of not answering the people back was the pivotal, decisive act?
Or should we instead ask whether Aharon’s failure included not tempering and guiding Moshe through the rest of the episode? After all, isn’t inaction also a kind of action?
Were not Aharon and Moshe at least partially responsible for one another? Is there a lesson here for all of us?