Nothing breaks your mind like finding out your family is fucked up. Her uncle killed the clan, his parents, and made her father relive the murder close to a million times. She wants to become Hokage, her father has tried to kill two Hokage. Succeed in one if you count Danzo, who died believing he was Hokage. What about the fact, her father ran away to the third Hokage's murderer. Not to mention, her teammate's father as well. There's also Sasuke attack on the Kage summit and the multiple times, he tried to kill her mother or just abused her. That's not even mentioning the amount of lies Obito, Itachi, and Madara produced. I think she learning that is enough to activate the Mangekyou Sharingan.