I am sorry -and not offense intended-, but you are missing the point.
None taken.
Yes, you or I would judge his actions like evil.
And it's not just us that would label his actions as evil. The world of Naruto labels his actions as evil, hence the bounty.
But the point of a neutral character is not whether his/her actions are good or evil or are judged like such. The point of a neutral characters is he/she does NOT care whether his/her actions are good or evil.
That is the problem with this, you're just tackling the neutral mentality of the character, while disregarding the action, which I find just as important if not more.
This is the case of Sasuke. Yes, he murdered and betrayed people -including friends and allies- to further his goals. But if he would have been convinced of he could avenge his clan for being a loyal, trustworthy friend and fighting poverty he would have done so. Because he does not care.
This argument hinges on a "what if" scenario.
And you could say the same with Orochimaru. You think he gives a damn if there are dozens of dead bodies strung up in his laboratory for experiments? Killing people was just a means to an end, he didn't care who suffered in the process to obtaining immortality.
Contrasts that with Naruto. If someone would tell him "you can become stronger if you kill one of your friends" he would tell "Go to Hell." That is because Naruto is Good-aligned (I would tell that he is Chaotic Good, but that is another history).
That is because Naruto actually cares about people's lives, something that is regarded as good in this series. One of the reasons why Asura was shown as the good guy in the flashback was because he had friends beside him. Indra was shown to be the bad lone wolf guy. He had no one beside him unlike Asura. Time and Time again, Kishi has made dozens of illustrations that show Naruto is good and Sasuke is evil. Naruto and Sasuke have always been represented by light and dark.
On the other hand, if Sasuke was Evil-aligned and someone proved to him that he can become stronger by feeding homeless people he would reject it.
Another "what if" scenario. We are past the point of that. Sasuke wants to burn the system to the ground, and delete the past, which means he wants to personally kill Naruto.
While his thoughts are apathetic to people's feelings, they're also being coupled with evil objectives.
Kishimoto is not wrong when he calls Sasuke a "neutral" character because by definition he IS.
And Kishimoto has said that Sasuke is pure, yet Sasuke himself has explicitly stated he is not pure. I let the series do the talking for Kishi, rather than hear what he has to say from an interview.