As a brazilian myself, i understand the point of view of some people, but, from i've seen of the situation, this is not cool.
Respect is the basic thing of every sport/e-sport, when the crowd started booing at Fnatic's entrance, i actually felt embarassed, because when LOUD entered the grand finals in Istanbul, no booing was made, and, when Fnatic was lifting the trophy, there wasn't a single soul in the stadium, like, dude, cant you stay 2 more minutes to show some respect for the team that provided such a good match for you to watch?