Said “boom” was exclusive to rich, already illegally armed people. Notice the total number of registered gun owners doesn’t even reach 1% of the population? Again, you have a distorted view on things.
You’ve got to understand Brazil has some loaded history, despite being a relatively young nation. Between 1964 and 1990, the country underwent a USA-backed coup which, unsurprisingly, tried to americanize its population in several aspects. As a result, you have pockets of people brainwashed to think 'murica is the best and everything they do should be copied – mostly old rich fuckers and their kids, as poor people could see, or rather were forced to see, the reality of things.