Rorschach: You see, Doctor, God didn’t kill that little girl. Fate didn’t butcher her and destiny didn’t feed her to those dogs. If God saw what any of us did that night he didn’t seem to mind. From then on I knew… God doesn’t make the world this way. We do.
EDIT: Quote above is from the movie.
Verbatim from the comic:
I personally think that Watchmen is a fantastic study* on all the different ways people react to that realisation.
(“Study” in the artistic sense rather than the scientific.)