>Can Brazilians be operators?
Sure, what our police forces lack in budget and equipment they make up for in experience and bleak acceptance of the inevitability of brutality and death. I'm obviously biased, but as far as I know the special units from São Paulo and Rio de Janeiro are pretty top-tier when it comes to urban engagements. Our army also has a jungle warfare training program that is supposed to be a benchmark for international forces, with units from other countries (including the US) coming here to train.
Bear in mind that all of this information has reached me after going through the propaganda machine that is mainstream media, so I might be wrong. I have not read or heard evidence of the contrary, though.
The militia matter is a somewhat complex one, involving vigilantism and corruption. Basically armed people (sometimes off-duty policemen/firefighters, sometimes retired policemen/firefighters, sometimes other) manage to take an area from drug dealers and establish control. They do everything the drug dealers were doing to make money (loan sharking, gambling, protection rackets, illegal connections to the electrical grid/TV/internet) except drug dealing.. since they have connections in the police force and local politics, they are harder to get rid of, and might even be hailed as vigilantes.
>>522170
Fun fact: that second picture is from a training exercise conducted by special police units in preparation for the Olympics. They had crisis actors and whatnot. It just so happened that the subway carts they were using had actual bullet holes from stray gunfire from the nearby favelas.
>>522180
It's also pretty neat that they get to have skulls on their emblems. I doubt that would go over well in any first-world country.
Taking all of that into consideration, it's worth noting that these "special units" are known for the leeway they have for dealing with suspects. It's cool to watch and read about them, but mentioning things like "due process of law" and "human rights" will only ear you a beating/electrocution/bagging.
Obligatory mention fo the "Elite Squad" movies:
http://www.imdb.com/title/tt0861739/
http://www.imdb.com/title/tt1555149/
Videos related.