I don't know, for some reason this made me really angry. But I don't understand why. From a neutral perspective, why do you think it bothered me so much?
It's obvious, isn't it?
Let's consider it simplistically. If someone criticises me, and in my opinion it's unfair, am I just meant leave my emotions in equilibrium? No, of course not, I would feel quite a bit of anger!
Whether this guy is right or wrong is irrelevant, when it comes to whether you are justified or not in feeling this way. Nobody is omniscient, and very few take unfair criticism well.