Even Olympics officials have said the conduct of the Brazilian fans is unacceptable. If you're not just trolling you can search out some quotes yourself.
Olympics officials does not equal "international". But please do show me that international condemnation of Brazilian fans. Or is 2% of the world considered international and only right and righteous today? I already know the answer but do go ahead.
I find it quite disturbing accusing Brazilians of "booing" at sports event when you could and can see this in events such as US Open, Wimbledon and other "clean and gentlemany" sports when the opponent is from some other country than US or UK. Let's not get into more "dirtier" sports now where booing is de facto standard.