Despite their name, the Peacekeepers regularly enact varying degrees of violence on the citizens they're supposed to protect. In The Hunger Games, Katniss remarks that the Peacekeepers turn a blind eye toward her illegal hunting and generally treat District 12 citizens with humanity, but by Catching Fire, most Peacekeepers that Katniss encounters are heavily armed and regularly attack civilians.
Throughout the films, Peacekeepers are also armed to the teeth with submachine guns, tactical rifles, and more, despite the fact that district citizens are mostly unarmed and harmless. While the largely faceless Peacekeepers add to Suzanne Collins' bleak dystopian universe, it's not hard to find examples of a militarized police state in our own world. Just this past summer, protests were often met by police forces whose equipment was more suitable for war than keeping the peace.
The Peacekeepers also serve as parallels for racial police violence in District 11. Peacekeepers are seen watching over workers gathering cotton in Catching Fire, and the birth of police forces in the United States is largely tied to slavery. Additionally, water cannons are used to incapacitate protestors in District 11, which is a direct reference to how police used fire hoses and water cannons against civilians during the civil rights movement.
