Some people just naturally hate Sakura, im pretty neutral, i dont like or dislike her, but i can name two reasons why people probably put more blame on her
1. People agree & disagree that she still has feelings for sasuke, but its pretty obvious, especially with this chapter that she still has some, and she shows it at the wrong time, their right in front of madara, and she's thinking about wheter or not sasuke cares for her, which was kind of stupid, yes naruto cares for sasuke, but its not the same way, but Naruto doesn't go like, "Hey Sasuke Look at me", "Sasuke look what i did" and etc, Sakura still likes sasuke, which is okay, but she shouldn't be thinking about sasuke noticing her, in the middle of a war
2. People think that sakura should not be in the fight with madara, because kishi follows the same routine, he makes her do one attack & then get's saved by naruto, and this has happened time after time, she never really had a good battle, unless she's with naruto or working with naruto & etc, the only time she had a good battle is when she fought sasori & that was in early shippuden, kishi always makes her play the "Damsel in distress" role all the time, and doesn't give her proper development unless it has something to do with pairings or something, that's why alot of people get at her