Why are Brazilian people so toxic?

Why is riot allowed Brazil to play on NA?

Riot has utterly no control over who plays where, nor do they care.

Everygame I get a person from Brazil, they are toxic.

Cultural as well as language barrier. They have gotten a lot better over the years, from first wide exposure to the internet. Not a great idea to generalize, though. Possibly the nicest person (and LoL player) i know is Brazilian.