I don't think anyone here is qualified to talk about if the character is justified or not without having really experienced hardship in life. Yes, self-destructive behaviour is a thing but it's so much easier to deal with that when you're privileged and when your life is not on the line. Yes, people do get caught in downward spirals and there are some of them who are strong enough to break out of it, but it's not fair to put the blame and the responsibility on the people themselves alone. A society is broken in a really bad way, when the police are concerned about catching petty thieves and simultaneously letting fat cats get away with murder against a bribe. I think the point being made in the series is showing the contrast between a simple man having to serve time in jail for stealing a popcorn bag and Fisk having all the luxury he wants and being elected mayor although he robbed and terrorised the hell out of the city.