It depends on the circumstances. If it was a hard fought game, with both sides having a pretty good chance and the end coming down to the wire, saying 'gg ez' is usually pretty humourous to me, because it's clearly sarcastic. Same when a team loses and says 'gg ez', although that one can be a bit iffy if they've been a bitch all game. They just seem like a poor loser sometimes.
It's when it's a complete domination, worse yet a 4v5, and the winning team is the one that says it, that 'ez' pisses me off too. That's why I never (rarely?) use it- how people will take it is very dependent on circumstances and the individual.
Also, I rarely see people use the word 'vehement', and I use it all the time so this post made me a little happy inside.