Well he did go after the crime bosses and various forms of Mafia and gangs in Gotham, which at the time was a really corrupt city. They then hired enforcers and hitmen to take him on. When that failed they moved on to better enforcers and hitmen. It turned into a cycle, until they were hiring the really dangerous ones who were just as likely to oust them and take over, or were candidates for Arkham.
The argument between the Imperium as it is and Chaos is the same as arguing in favor of Nazi Germany over Social Anarchism.
Hes the dictator because he knows whats best for humanity not your gods who just want more souls to feed on!
Yeah, because the Emperor totally doesn't feed on the souls of his Empire. Totally. Pretty sure he completely fucked up with the whole "Horus Heresy" thing. That "Imperial Truth", too. Would you maintain that if you were Jewish?
The Emperor is a traitor to Mankind! Why won't anyone just understand that!? He lead us down a path of slaughter and darkness, filling our minds with his Imperial Lie, censoring the Primordial Truth. He should have built his Imperium as a Theocracy dedicated to the Ruinous Powers, but he did not! He was a fool and a madman, and he will burn in hell for his crimes!