Here's why:
* Dumbledore was terminally ill with a curse: He had been secretly suffering from a curse that was slowly killing him.
* Severus Snape agreed to kill Dumbledore: This was part of a complex plan to ensure Voldemort's downfall. Snape, as Dumbledore's trusted friend and confidante, was the only one who could carry out this task without raising suspicion.
* Dumbledore's instructions: He specifically instructed Snape to kill him, and even provided him with the means to do so. This was a deliberate act, not a murder.
* Dumbledore's intentions: This act, orchestrated by Dumbledore himself, was a crucial step in a larger strategy to protect Harry, weaken Voldemort, and ultimately defeat him.
While it may seem like a shocking act, it was ultimately an act of self-sacrifice for the greater good. Snape's actions were driven by loyalty to Dumbledore and his desperate desire to protect Harry.
Let me know if you have any other questions about this complex event!