My experience was similar. There were definitely aspects of the history which were somewhat familiar to me. The details, however, really fleshed it out.

What was entertaining / illuminating was asking my more-aware American friends questions based on the book, and seeing what they were, or were not, aware of. Helen Keller's an interesting example to use, because she's taught virtually universally in primary school as a hero of the disability-rights movement: she overcame deafness and blindess to become an author and speaker, schools and childrens' books teach ...

... but not what she spoke and wrote about. Which tends not to fit into the public-school curriculum as well. (Though perhaps its one of those submarine lessons, a seed planted to emerge later.)

I've had a lot of fun asking questions about that, watching peoople look up the story, and minds open. (Usually.)

Loewen was an absolute hero. His passing is sad, his gifts are greatly appreciated.