Please, do not generalize Brazilians like that.
I know that there are tour groups that are rude and terrible, but we're not all like that. I also hate these groups, but I'd never do such things as lots of them do (I know of some people that went with groups and caused no problems, I think that the groups of mainly teens are worse probably)
I've been to WDW 4 times, about to return for my fifth and I was ALWAYS polite with people and followed all rules (even on my first time when I was 5 and didn't speak english.

Actually I asked my parents to start learning english right after we returned from this first trip in 1989, cause I had LOVED WDW

and wanted to understand everything on the second trip!

).
I'm saying all this because I know that many of you have met these groups and hate them, but do not think that all Brazilians are like that because we're not.