Agreed.
Moreover (and I mean this kindly) - toughen up! There are people around that will act as this fool did. If you're going to let each and every one of them upset you then you're only going to make your own life a misery.
I know it's hard to do but forget it. The guy's an idiot and you ought not waste your time worrying about idiots. You've better things to do with your energies. As suggested earlier, and if necessary, let the frustration out some other way. For example, find a decent climb and sprint it! Turn your anger to your advantage, burn it off training!