Poverty increases desperation and social alienation. Feeling connected to the benefits of being a part of a society increases prosocial behavior. Disconnection from those benefits decreases prosocial behavior. Impunity and isolation from normal society because of extreme wealth can also decrease prosocial behavior. Some people are shits regardless of the situation. It’s a game of tendencies and risk factors. We all want to build a society in which people’s work is rewarded and bit of bad luck doesn’t doom someone for life. Extreme inequality makes that harder. This is all pretty well-trodden ground.