Yeah but books wouldn't explain the amount of inside info at her young age. She knows too much of the culture. I believe something will come out in the last book.
The witch hunt(yuk yuk) for Sirius Black in GOF and OOP reminded me of the Clarence Thomas mess. It's not the weight of evidence but the seriousness of the charges that is important. I loved the "Oh whatever he died" response when the PM mentions Black to the Magic Minister in HBP. The Magic Minister should be a corporate case study in covering one's arse.
According to JK all that stuff Hermione learned from Hogwart's a History and other wizarding history books is basically just a device to explain things to the reader. She said in the interview on Muggle.net that's why Harry will never read those books, because if he reads them then he won't need anybody to tell him stuff and given the narative style she's chosen the only way to tell the reader is to tell Harry.