Well, lets see if I can take what's likely to be a shockingly unpopular view here.
What's a player to do when he's frustrated by a team under performing? Keep his mouth shut for the sake of some abstract bulls**t concept of "team loyalty"? The team is playing like sh*t. Griffin's playing like sh*t. Does he go to Shanny and voice his concerns? (P.S. I'd love to know if that happened and if so what kind of response he got.)
"Team unity " is a wonderful ideal but when the unity seems to be getting in the way of not playing way below what the team is actually capable of I can understand Garcon's frustration. Hell, I'm pretty damn frustrated with the team right now.
Was his outburst a violation of propriety? Probably. Was it disloyal? Well, IMO, only to those who think loyalty means "support us without criticism even when we're f**king up big time." Sometimes true loyalty means calling somebody on their buls**t.