It is impressive but i really think that those numbers need to be properly discussed as you said.
In South America you have places (like favelas in the north of Rio de Janeiro) which are like Saturn and that unlikely in the rest of the world, they're well marked and well separated from the rest of the city. You cannot go there, they're a completely different reality, they have parallel laws, and therefore they compromise the true purpose of these statistics. I cannot find the article, but something like 85% of the homicides in Rio, happened inside the most dangerous favelas, and mostly involved drug dealers.
Anyway in 2015 in Sao Paulo (12,000,000 people), there were 650 homicides.
In Rio de Janeiro (6,500,000 people), same year...1370 deaths.
In Chicago (2,700,000 people) 460 homicides in the same year.