The article doesn’t seem to show any context to this, are equally poor countries on other continents better or worse?
My guess is the main problems are probably poverty inequality and corruption. Catholicism may also be a problem, as every crime can be absolved by the church, and Catholics are free from the ultimate personal consequences of their crimes.
So the corruption and inequality may create a sense of need for many people to need to balance the injustice, and combined with a lack of perceived ultimate consequence may be a toxic cocktail that stimulate violent crime.

This however is pure speculation on my part. But it seems evident there must be some kind of social factor to cause things to be so bad.