It is,isn't it? Just some kind of childish temper tantrum over secret clubs and not being in on them. Because Steve was mad only with Tony. As if he had been the only one to blame, as if the others hadn't had any choice or participation in forming and then keeping alive the Illuminati and any of their following endeavors.

~Beware, Spoilers!~

And then after the Gauntlet's 'disposal' the others ask him if he isn't going to do something about Iron Man and he says he'll 'take care of it tomorrow' -if I remember correctly- before giving Rulk what, letting Tony go all sad thinking he's been effectively kicked out of the Avengers over the Illuminati that weren't even active anymore, would be one heck of a hypocritical speech about redemption and second chances and how it's all good as long as you are trying to make up to your mistakes with a straight face.

Then he agrees to reform and be part of the Illuminati.

~End of Spoilers~

Geez.