What if they are adhering to social norms? What if the way they are acting is perfectly acceptable in Brazil? How is this any different that complaining about "fat" or "lazy" people who look "perfectly fine" using
ECV's and not knowing how to drive them? I am not sure why, but threads about these tour groups seem to be some of the most blatantly racist threads on these boards.
Here are some simple truths:
(1) any large group of people traveling together can cause issues within a theme park (lines, waits, etc.
(2) take ANY group of teenagers and put them together away from home and they are going to act obnoxious to some degree
(3) chanting in a line is far less annoying that people talking through rides or taking flash pictures during dark rides.
(4) anyone that has issues with large numbers of people may find that WDW is not the most magical place to vacation.
A good plan and some flexibilty is all that is needed to avoid drama associated with any tour group.