Did the thread maker ask about why do people hate on Kishi or why do people hate on mangaka? -_- (Rhetorical, don't answer.)
It's not mainly due to the fact that it's because they're fanboys. It could also be because they really really liked the manga at one stage and got really angry with how it ended up progressing. After tolerating for about 20 chapters, you have to give up on the manga and hate the mangaka for getting you to like the manga and destroy it, frame by frame.
(My own views, yes, but they're not about Naruto; mind).
It's not mainly due to the fact that it's because they're fanboys. It could also be because they really really liked the manga at one stage and got really angry with how it ended up progressing. After tolerating for about 20 chapters, you have to give up on the manga and hate the mangaka for getting you to like the manga and destroy it, frame by frame.
(My own views, yes, but they're not about Naruto; mind).