A Tzaddik dies and we get forgiveness????????

The Rabbis explain why the passing of Miriam is placed next to the description of the Red Heifer. They say to teach us that just as the sacrifices bring forgiveness,so too , the death of the righteous brings forgiveness.
Now this is strange. For in the story of Miriam's passing both of her brothers are punished for what appears to be minor sins if they are sins at all. Now how does the punishment of her brothers Moshe and Aharon have anything to do with forgiveness?
An answer might be that Moshe and Aharon realized that the people could not stand up to the
level that they were at. As a result, their expectations of the nation's capacity had brought them to unrealistic demands.
Instead of blaming the nation for their shortcomings they accepted responsibility for providing faulty leadership. In doing so, they were saying to G-D,"we erred in demanding too much from the people-You oh G-D ,too, lessen your level of expectation from them!"
This of course brought forgiveness, as we could be excused for failures to rise to the levels
that had been originally demanded. For G-D accepted the position of the Tzaddikim that it was their fault for not inspiring the people to reach a higher level. Therefore, they said the punishment belongs to us not to the Benay Yisroel.
So, the death of Miriam brought G-D to lessen the demands on the common man. In that equation the Righteous had to accept punishment for their failure, not ours-even though in truth we messed up. Moshe would not let the second generation to get punished in the desert for fear that we would never leave.
Better I should suffer rather than this new generation which needed to keep its' enthusiasm going in order to take and settle the Promised Land.