I can't understand the hatred towards Sasuke. Imagine Batman would find out that his parents were mass murderers and Joe Chill was the good guy, along with... other criminals. Don't you think that would make him question his existence?
The Elders of Konoha ordered the extinction of an entire clan because they feared a rebellion. But they also ordered to kill innocent children that probably didn't know what was going on (Sasuke was one!). The order "Eradicate the entire clan" didn't differentiate between innocent people and true enemies of the system.
Sasuke just wants to take an eye for an eye: If the elders didn't differentiate between innocent and "guilty" people, why should he do? Isn't this the ideal punishment, the revenge of innocent lives that have been destroyed before? Moreover, Sasuke's jutsu Kirin perfectly demonstrates how Sasuke thinks of his life: The mythical creature Kirin punishes evil and is a ghost of revenge.
Sasuke's hatred is indeed not rational. It is emotional. I would like to know how the people that call Sasuke "stupid" would react in sasuke's situation. If their emotions would be "rational" enough to hate the right people. I wouldn't act like Sasuke, but you can't blame him either.