He didn't even get that mad. And he was barely throwing a temper tantrum, he just vented his rage by calling Varian a fool and saying he will stop at nothing to protect the world. I don't know how vowing to protect a planet is the same as a temper tantrum but okay MMO-Champion.
Anyway, his mind is in the right place, he would prefer the world to unite and defend against the legion, rather than getting obliterated in a 3 way war. I am dumbfounded how some posters here cannot understand this and believe he is evil because he got angry when Varian made a terrible decision