interpreting motivations?

This movie was unusually light on spoon-fed explenations for everyone's motivations. But here's what i took from it:

The american dude: a life-long loser who stumbled into a bunch of racists, and since they were the first people in his life that offered him some semblance of self-respect he stayed with them. They all bond over their nighly missions to find mexicans.
If he had f.e. been rescued by a church he'd be singing halleluja instead.

The mexican dude: rich macho-dude. More interested in being seen as 'the savior of mexico' than in establishing peace. A macho creep with no sense of personal boundaries, especially towards women. He hates the government because he wants to be a leader and not a negotiator (and presumably also because rich people hate governments for tax-reasons). His vigilanty-group predictably becomes yet another terror-group.
Afaik this whole set-up appears to be pretty standard for crime born from poverty and social inequality: the 'soldiers' are poor people with no self-respect, the 'commanders' are spoiled rich kids with no sense of boundaries and no respect for life.

A cartel is a bussiness, and it seems that in countries where huge levels of social inequality mean that legit companies experience a plethora of power-abuse the step to organized crime is small. In Mexico the location makes for easy drugs/trafficking-money, which is another incentive for crime.

Poor mexican people are stuck in that ultraviolent nightmare, desperate for the return of 'rule of law' and the return of the 'monopoly on violence' to a sane government.