Yeah killing someone to "save" them was pretty stupid of Sakura (One of the reasons I don't like her) but going by canon she did it because she didn't want to see him fall into darkness, she was willing to be hated by Naruto for that.
LOL, Hinata is a meat shield I agree, but I was just saying that both her and Sakura "worked harder" than Naruto....
Funny i remeber Sakura doing exactly nothing other then using Naruto to get Sasuke. All Hinata did to get Naruto was stalking him and neji playing matchmaker. Naruto on the other hand made a promise and sacrificed his own happyness for Sakuras sake.