There is also a racial component to the discrimination in Brazil, as Afro-Brazilians are pushed aside for the gentrification and development of land that has been theirs through forceful government confiscation ("eminent domain"). Race in Latin America is much more fluid than in the United States, with much more mixture between the races, so the discrimination can be said to be more of "colorism" or based on phenotype rather than genes.
There is also the issue of waters in and around Rio contaminated due to tons of raw sewage being pumped into them every day. Because of this, athletes have been advised to avoid sticking their heads underwater due to very high levels of viruses and bacteria that can cause illness. On a brighter note, some of the people that regularly fish in these waters and consume the fish likely have very strong immune systems that have adapted to the environment, though this does not apply to the tourists. Personally, I have been to Rio and surfed and swam at a couple of these beaches (Ipanema and Copacabana) with no problem, so I think the dangers are overhyped, but still important to keep in mind.
It will be interesting to see if Rio is prepared for the upcoming games.