Might as well just throw in a few lines:
Sasuke's ideals clash and do not coincide with Itachi's. Once your philosophies are different, it's bound to create a conflicting ideal. Sasuke, despite loving his brother, always valued his clan more than the village. Itachi, despite adoring Sasuke, devalued his Clan before his jingoistic ideals for the Militia set up, and he died believing in them.
Till the end, he kept stating that no matter what, 'he's still the Leaf's Shinobi' - this shows that he has no real identity beyond that forged in the Light of 'will of fire'. Sasuke has created an identity for himself, away from the ethos and dogmas of the Leaf Village, where Shady politics keep the system afloat. Sasuke found something beyond that, an ideal - a restoration of his Clan's honour by bringing down the man that ended it.
Imagine Sasuke discovering that Itachi was nothing more than a fool in the Village's higher ups scheming, a cog in Danzo's plan to obtain the Sharingan so that he would be able to control the Nine-tails and in turn the village - something he forever desired. This was bound to veer his anger, channel it towards the actual cause of contention. It's a natural human response. What you feel about this, isn't of any value, as you keep pushing aside important character aspects.
Itachi's identity and character traits are far stale, stagnant, and run-of-the-mill in comparison. The fact that Itachi ignored Shisui's confessions that this man stole his Sharingan, makes him that much more despicable. I hear people blubbering how selfless this character was, yet truth be told, Itachi was the most selfish individual in the entire manga. He didn't care about the circumstances surrounding the Coup and chose to side with the Leaf, as it supported his own brand of idealism. It's far more irritating and redundant as a mode of characterization than anything else.
In fact, had he himself been trapped in Izanagi's loop to discover himself, he never would have found anything to define as an identity marker for himself. What is Itachi's identity? The answer is, nothing. This is why Sasuke's responses and reactions make sense - they may be outrageous, audacious, and vehement, but they are real and they helped him forge his own identity, which Itachi has always lacked. Even after his death, he's nothing more than a man who sought Leaf's shade and label. An empty man, sans Self.
Here is your criticism.
