Is it really accurate to call these groups gangs at this point? They are not gangs in the sense that people in the US or Europe would understand. They are not groups of criminals engaged primarily in economic crimes. They are basically armed autonomous militants. Their main activities are political and governmental. Most of the killing is for control of territory they oversee.
In essence Haiti has become a failed state and these groups are vying to control that power vacuum. The term gang is more misleading than clarifying and I have to wonder if there is some unconscious racial bias at play with media coverage.