When Chris Jericho disrespected the flag in Brazil everyone acted like this was unheard of. Well I said it wasn't the first time something like this has happened. I'm sure there are more examples than I could think of. Most of the time when a heel wants to get the crowd against him he will say insulting things about the city or country or in some cases disrespect their flag. Likewise, when a heel is from another country it is common for him to bring his country's flag with him to the ring just to piss off the local fans. In that case, its not uncommon for the baby face to come out and smash or rip that flag to the delight of the audience.
In Chris Jericho's case he was the heel and he wanted to get the crowd in Brazil to hate him. That is his job. He wants to make the crowd cheer for his opponent CM Punk.