u/Nearby-Condition-675

An analysis of his actions reveals four key areas that make fans consider him the worst Hokage and the culprit of many tragedies:
Hiruzen created a system where he remained the "pure" leader, while Danzo and his organization, Root ANBU, did all the dirty work. He knew of Danzo's brutal methods, but turned a blind eye to them for the "greater good," which ultimately led to the destruction of the Uchiha clan and the creation of the Akatsuki faction (through manipulation of Hanzo and Yahiko).

Before his death, the Fourth Hokage requested that Naruto be considered a hero. Instead, Hiruzen kept the boy's origins a secret, leaving him to grow up in complete isolation, poverty, and the oppression of the villagers' hatred, doing nothing to stop their cruelty.

Having caught his student performing horrific human experiments on infants and villagers, Hiruzen could not raise a hand against him and allowed him to escape. This cowardice cost the lives of thousands of people in the future and led to the attack on Konoha, in which Hiruzen himself died.

Sarutobi delayed resolving the looming conflict until the very last minute. As a result, Danzo seized the initiative, and Hiruzen effectively allowed the entire burden of the genocide and the status of traitor to fall on the young Itachi Uchiha, leaving Sasuke an orphan and deeply traumatized.

In conclusion: The worst hokage to ever exist