He was mature enough not to have any inhibitions about using such a technique, knowing that it could give him an advantage in the fight against Kaguya. That wasn't even the point though. If you haven't already experienced it, I think it will be difficult (maybe impossible) for you to understand. Just...remember this when you hit a really low point in your life :/
He isn't mature. Maybe you should look up the word mature.
Isn't it logical to try to befriend everyone? No one wants to be hated/alienated, right? And people who are hated/alienated often end up hurting lots of other people. It could all be avoided...In fact, Sasuke agreed with Naruto in the end. Go read 699 again. If Naruto is naive, then Sasuke is equally naive (if not more so).
Not everyone will want to be your friend and not everyone deserves to be your friend(Obito) so this logic is not always acceptable. Your optimism is disgusting. Not everything is about unicorns and rainbows.
Sasuke might be naive(to an extent) but at least he chooses to mind his own business and not try to force himself onto other people that don't want to be bothered by him. See where I'm getting at? Probably not.
Befriend with everyone is a better feat than killing everyone, mainly in a ninja world.
And when did Sasuke ever kill "everyone?"
You said he's being realistic ? Tobi, for example befriended him (easily) to destroy Konoha, before he just wanted to kill Itachi and (probably) return to Konoha and at the end he wanted to make a revolution...
Your examples are retarded, considering that, that's not what I meant about being "realistic." Sasuke changes just like any other 16 year old boy. When a teenager gets tired of one thing, he changes to something that he sees better.
In Sasuke's case, he had just got finished defeating his brother, or being apart of his brothers death. After that he heard the truth about his brother from Tobi, so he made a new goal. Did you expect Sasuke to just forget about Danzo and go back to Konoha. By that logic the manga would have no plot, so Kishi had to make Sasuke do something else, and it was a good move. Sasuke killed Danzo. After that he went even darker, but this was to make Sasuke more of a villain than ever, but he decided to wait and take Itachi's eyes. Itachi's revival stopped Sasuke from destroying Konoha so he defeated Kabuto along his brother and revived the Kage to help the SA.
After that he announced that he would be Hokage.
They defeated Madara and Kaguya, so then he declared that he wanted to kill the 5 kage and start his own revolution. The problem with this, is that most of you reprobates take this too literal, as this was just a way for Naruto and Sasuke to finish things, as Kishi needed a way to end Sasuke's darkness and end him off on a good sign.
Sasuke's sudden changes are what make the story persist and it keeps moving. You claiming that this is a bad thing only proves that you don't even understand how Kishi writes Sasuke and you probably just skip every panel with Sasuke because he makes you upset.
This guy doesn't know what he wants
If he didn't know what he wanted then he wouldn't be making goals now would he?