Throughout the Harry Potter series, Albus Percival Wulfric Brian Dumbledore acts as a benevolent force who guides Harry and his friends through adventures both large and small. However, when you look at disturbing facts about Dumbledore, it’s clear he's irresponsible at best, and legitimately evil at worst.
One can make the case about Dumbledore's depravity surpassing Voldemort's. After all, both wizards needed Harry to die for their plans to work, but only Dumbledore hides his true intentions from the Boy Who Lived.
Readers are rightfully wary about many terrible things in the Wizarding World and the Harry Potter movies: the mistreatment of house-elves; the existence of a restrictive sorting system separating students into houses; and Dumbledore’s entire approach to life.
When the Basilisk begins to terrorize Hogwarts and petrify students left and right, Dumbledore doesn't lift a finger. One might assume an empathetic headmaster would close the school until they settle the animal control problem - or better yet, destroy the snake, but instead, he lets a group of second-year students take care of things for him.
Once students start getting petrified, Lucius Malfoy calls for Dumbledore's suspension. It's the appropriate response when the headmaster of the school refuses to take action against something harming the students.
At the onset of the Harry Potter saga, Dumbledore commits one of the most heinous acts toward a child: he abandons it. The Headmaster of Hogwarts doesn't just leave baby Harry on a doorstep, either - he deposits him with the abusive and racist Dursleys.
According to the story, Dumbledore leaves Harry on the Dursleys' front steps to invoke the magic of the bond of blood, which Petunia Dursley (Harry's aunt) seals when she accepts Harry into her home. However, this kind of magical hand-waving ignores the fact Dumbledore's main concern involves casting a decade-long spell instead of ensuring a child's safety.
Perhaps the most damning critique of Dumbledore comes from his longtime confidant Snape, who accuses the wizard of essentially grooming Harry to die. There's a subset of the Harry Potter fandom believing this.
If Dumbledore allowed Harry to die at a young age, he could have saved the lives of thousands, if not millions, in the Wizarding World. Instead, he allows Harry to mature and eventually sacrifice himself to kill Voldemort.
Dumbledore lets Harry grow up as a Horcrux because he needed the Boy Who Lived to willingly give up his life while facing Voldemort, thus creating a similar protective spell like the one surrounding the Dursleys' home.
When Voldemort kills Harry, he destroys a piece of his soul, allowing Harry to come back to life and destroy Voldemort once and for all. This plan seems to rely heavily on luck, as well as a particular set of circumstances needed to fall into place for a satisfying payoff.
Throughout Harry's time at Hogwarts, Dumbledore seems complacent with his Potions Master, who delights in intimidating every student on campus, especially the orphan whose parents died by the hand of the evilest wizard in history.
At no time does Dumbledore tell Snape to act professionally with his students, which is tantamount to allowing him to continue the abuse.