Allan Moore has a strange style; he takes something and make the darkest version you can imagine. But it is not dark because the dark is cold, NO! He wants to represent a version of an altruist world from different points of view.
(Warning Spoilers from Watchmen)
For example, in Watchmen, the characters of Watchmen search to make the world a good place. At the beginning, they use an empire of law like is USA, but after the superheroes become illegal anything needs to break the law to impose it. When the protagonist gathers to stop the violence in the streets, the comedian laughs of it, because he was in Vietnam, he saw the methods of USA for keeping their civilization. Ozymandias saw his friends in the past and he release their plan to simulate an alien invasion that killed millions of people in the process, with the objective to avoid a nuclear war. The climax of the history happens when he says: "I am not the villain, I am the hero, I did it 35 minutes ago."
(End of the spoilers from Watchmen)
This story provokes the reader a thing: How has the reason? Is justification? This is the objective of Moore, he likes a reader that empathizes with the characters and the things. He applied this to many more stories. In “V from Vendetta”, V is a terrorist, but it does not justify his methods, what is good and what is bad. This is Moore's darkest style.