Why Sasuke Went Off The Deep End by Raven Wilder
Sasuke has officially been dubbed a bad guy by In-Universe legal authorities ever since the end of Part 1, when he abandoned his village in order to join Orochimaru. But something to bear in mind is that, while Sasuke did technically betray his village, Part 2 reveals that he was planning how to usurp/assassinate Orochimaru from the moment he joined his organization. Part 2 also gives us scenes where Sasuke, despite spending three years as Orochimaru's pupil, refuses to kill anyone who's not a Complete Monster. Given this, I'd say that, until he met up with Tobi, Sasuke's actions were reckless and irresponsible, but weren't actually immoral.
It's only in the aftermath of Itachi's death that Sasuke truly becomes a villain. Here's how I interpret his mindset at that point:
He's spent most of his life planning to kill Itachi; he refers to this as his "reason for living". Then he finally achieves his goal and . . . he's not happy. He comes face-to-mask with the other man responsible for the Uchiha Massacre, but now all Sasuke's drive and passion is gone; he can't think of anything except to ask to be left alone. I believe that, if Sasuke had been left alone then, he would have killed himself, having found his purpose in life to be empty and unfulfilling.
Then Tobi drops The Reveal about how the Leaf Village ordered the slaughter of the Uchihas and how Itachi, forced to commit such an atrocity against his own family, still loved Sasuke, tried to protect him, and was ultimately driven into suicice-by-proxy. Suddenly Sasuke is given an explanation for why Itachi's death brings him no joy, because, even if he could only guess at the truth through little hints (Itachi's tears after the massacre, his dying words to Sasuke), on some level he knew that Itachi wasn't the person he should be angry at.
Tobi gives him a new target for his anger, an anger that's only intensified after being manipulated into killing his brother. And Sasuke, who had been left with no reason to go on living, jumps at the opportunity to have a purpose for his existence again. And this time he expands the scope of his revenge beyond the people directly responsibile for his suffering; he starts targetting everyone remotely connected to them as well. Why? Because deep down he fears that, if he kills Danzo and the other village elders, all that will happen is he'll once again feel the way he did after killing Itachi: empty, joyless, without the will to live. He swears revenge on the entire Leaf Village, and even on the entire Shinobi world, because he recognizes that this is a goal he'll likely never be able to fulfill, that he can spend the rest of his life on it and never finish. Because if he does succeed, if he kills everyone he's sworn vengeance against, he has nothing but despair waiting for him.
Until Naruto can do for Sasuke what he did for Gaara, show him that he can have a purpose in life other than violence, Sasuke's only options are a never-ending crusade of revenge or an emotional emptiness that will drive him to suicide.
Analysis of Sakura's recent actions through the lens of her being a symbol of human weakness
Contains spoilers for the Summit of the Five Kages Arc
While some readers are accusing Kishimoto of sexism in how Sakura has been portrayed recently, her portrayal is consistent with, and especially indicative of, her status as a symbol of human weakness. Sakura is intelligent, determined when it counts and considerate of her friends, but her judgment is often swayed by emotional issues, such as her feelings for Sasuke, her feelings of guilt toward how much Naruto suffers, and her feelings of responsibility toward both. This often leads her to act without thinking, or make decisions that people will not want out of the belief that it is for their own good, but her attempt to deny those feelings in trying to kill Sasuke fails, and shows that feelings, for better or worse, will always impact human judgment.
These aspects of Sakura's behavior are frequently shown early on. In the Land of Waves Arc, she finds a seemingly dead Sasuke and says that she memorized the rules of shinobi conduct, especially not showing tears in a mission, before crying over his body, showing the difference between knowing what to do and doing it. Kakashi has her in mind when suggesting that Team 7 choose individually whether to enter the exam, knowing that if she knew her approval was necessary, she would go along out of obligation to Naruto and Sasuke. She plans on withdrawing from the exam at the tenth question so that Naruto, whom she believes cannot answer it, will not lose his chance to become a Chunin, despite knowing he wants to take a chance. For similar reasons, she later threatens to tell the instructors about Sasuke's curse mark if he doesn't withdraw, not knowing that they already know.
Sakura's actions toward Sasuke are often motivated by guilt. She failed to convince him to stay, and was not allowed to participate in the mission to retrieve him (presumably partly due to not having any useful abilities and partly due to Sasuke needing to be brought back by force). She also feels guilt with regards to Naruto, who suffers as a result of repeated failures on his quest to bring Sasuke back, and hopes to ease his burden.
Sakura begins to despair when hearing of the order to kill Sasuke and of the rest of the Konoha 11 going along with it, realizing how far Sasuke has fallen, how difficult reaching him before those out to kill him do is, and that there is no future for him even if she brings him back. Feeling responsible for Naruto persisting in order to fulfill his promise, she sets out for to convince him to abandon his search. She makes a Love Confession that Naruto, despite his feelings for her, refuses to believe, remembering how deep her feelings for Sasuke were and doubting that she would give up on Sasuke so easily. The attempt fails and Sakura leaves to kill Sasuke, not telling Naruto because she does not trust him to stay out and wishes to deal with Sasuke herself.
Sakura's attempt to kill Sasuke fails as a result of her attempting to do what is essentially impossible for her in order to take the responsibility of dealing with Sasuke upon herself. While Lee, Kiba and Sai have no special attachment to Sasuke, and no qualms about killing him, she, partly assuming (most likely correctly) that the four of them combined cannot defeat him in open battle, and possibly partly because of wanting to do this herself, gases them and knocks them out. She then attempts to kill Sasuke herself, but is unable to do it- not only has she never been shown killing anyone before, but while she may have accepted killing Sasuke as the only solution, she has not abandoned her feelings for him. By contrast, Naruto spent much of the Summit of the Five Kages arc dealing with his thoughts on how to consider Sasuke and how to bring him back with him being wanted dead throughout the world, managed to find a solution (bring him back or die along with him) that did not force himself to go against his own values.
This is not to say that Sakura's feelings are inherently bad or that all her decisions based on them have been wrong or for the wrong reasons. Her desire to no longer let her teammates down leads her to take on the Sound Ninja in the Forest of Death to protect Naruto and Sasuke. Her efforts to become strong enough to bring Sasuke back lead her to study medical ninjutsu under Tsunade, enabling her to rise to Chunin at 14 and have better statistics than much of the Konoha 11. These skills prove useful in her battle against Sasori and without her, Chiyo would most likely not have won. Sakura's determination to help Naruto and Sasuke enables her to find the courage to escape from Sasori's gas by using a paper bomb. In these cases, Sakura's feelings are a source of strength that help motivate her to become strong enough to accomplish her goals.
As the end of the Land of Waves arc and Sakura's own admission while confronting Sai about his claims of emotionlessness shows, feelings can often cloud judgment, but people cannot completely deny or rid themselves of them. Sakura, being an especially shining example of that aspect of humanity, must work especially hard to deal with her feelings, and this conflict lies at the center of her character in Naruto.