TL;DR
Naruto has actually had a better life than Sasuke, and thus in a way validates how shitty Sasuke's life is. Sasuke wanting to kill the five Kage is insane...but he's been kind of led to this point. Can Kishimoto write something that's not an asspull with the situation he's created?
At this point, Sasuke and Naruto have had completely different experiences with the Kage, and the world, in general. Note that aside from the exclusion for being a Jinchuuriki, Naruto has had it pretty good. Just try listing all the adults that Naruto was able to benefit from. People went out of their way for him, at times. Sasuke didn't get the same treatment. Kakashi did try in his own way, but failed. Whereas Orochimaru offered him power; which translated into justice against Itachi at the time.
Justice works in two ways: punish the criminal and rehabilitate the victim. Neither of these things happened. Itachi was in self-imposed exile as a cover-up for a failed coup d'etat. Sasuke didn't have an Iruka-like figure bending over backwards to give him any form of social support. His going insane to obtain justice by his own means is the inevitable third option in such a heartless world.
His conversation with the four Hokage really only served to further prove how unreasonable the current world is. The stories that they had to tell were complete bullshit, with the Second being the only exception.
The First was only good at fighting. And in his time, there was only violence. As revolutionary as he was for establishing the village system, his final fight with Madara proved he was as susceptible to the cycle of violence as anyone else.
The Third failed to prevent a genocide. What's worse (yes, worse than a genocide) is that he let Danzo have political and military power. If Hashirama proved that leaders can be fallible, then Sarutobi proved leaders can utterly fail.
The Fourth had no political achievements. Notably, he did nothing for the Uchiha.
The Second was the only person that was upfront and said, "Look, your people had a potential to cause trouble, but I gave them the opportunity to help, instead."
By the time all the talking was done, what was made clear is that: the world is fucked up, which fucks people up, who then fuck up the world; therefore cycle of violence, therefore pain, etc. Sasuke, by surviving the massacre and by having this conversation, is far more intimately involved with the reality and suffering of the ninja world. In contrast, Naruto was removed from the circumstances that traumatized people like Tsunade, Kakashi, Obito, Madara, Neji, Gaara, etc. He's a compassionate observer, but ultimately did not know what it's like to have gone through this kind of loss.
So why is Naruto having a better life than Sasuke important? Because I feel like Kishimoto's written himself into an awkward situation where he has to resolve Naruto's and Sasuke's characters, their relationships to each other, AND how either of them will approach saving the world. The problem is, he's led us to believe that Sasuke is an irredeemable psychopath, and Naruto's only real answer is, "I won't give up." It'll be hard to say whether the new chapter is going to be able to deal with all the baggage left in the air.