A shady organization answering strictly to the Hokage? It's ripe for abuse. Orochimaru said it best;
Even Obito, who wants to push Sasuke away from Konoha, cannot bad mouth Sarutobi and says he was attempting negotiations. The Massacre was the cause of discrimination which no one man can end but their treason cost them their lives—Hiruzen tried, earnestly, to stop it.
Zero inaction. The discrimination began with their appointment as the village authority. Orochimaru calls Tobirama out for it.
If anything, we should be chiding Hiruzen for wasting so much time instead of working from the get-go to take down the Uchiha.