Not everyone becomes a gangster out of poverty. Some people who become criminals had good upbringings, but may have been bullied badly when they were kids. They can struggle their entire life searching for respect or even for being feared by other people. In the end these people can become criminals, petty criminals but often also organized criminals.
All this is not justifiable, but when you look deep into the human psyche it is 'understandable'.
In the end most people have some redeeming values, even mobsters.