system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Why did the Dementors stay loyal to the Ministry during the First Wizarding War?

Following the return of Voldemort, both he and Dumbledore regarded the idea that the Dementors would defect to his banner as a foregone conclusion. While the reasons they give are sound and they are ultimately proven right, this begs the question of why they remained loyal to the Ministry during the first war. So, what changed between the first war and the second that made the Dementors more inclined to change their allegiance?
gpt
The Dementors don't have an allegiance to any side, they just want to feed on people's emotions. During the first war, they got a steady stream of victims as the cells of Azkaban were filled by Death Eaters, so they felt no need to leave. 

When the second war came around, Voldemort freed all the inmates in Azkaban and therefore the dementors left to find new people to feed on.