To avoid them on-site, stay in the moderate or deluxe resorts.
We had a vacation a few years ago in which our boys wanted to stay at ASMo. They loved the resort, but easily half of the people there were from Brazil. We had a lot of fun with them, so no problems to report, but they are there to have fun, so you have to see it for what it is and go with it. Like the cheerleader crowds - lots of noise.