Thread:KNN005/@comment-25266931-20170304160915/@comment-26397825-20170315030853

While they describe the people as thieves and scoundrels, they specifically mention that Mistral is the home of the black market while Vacuo is more about survival. Basically, Mistral is the organised crime, the ones who are criminals in every sense of the world, while Vacuo are the ones who steal to survive and fight to keep what they have. They're selfish and individuals rather than organised crime like Mistral.

Remember that Sun is from Vacuo originally, and while he doesn't have second thoughts about stealing food to eat, the thought of attacking someone purely for perceived injustice (the White Fang) is strange. He's not a criminal, just loose with laws.

Or that's the impression I got from various references in the show.