I think you are assuming a certain level of reader awareness and open mindedness as well as counting on individuals to have learning experiences, as you've claimed this thread to be, but which come at the expense of another's time, energy, personal pain and story put on parade (possibly for the umpteenth time).
When there isn't a parent/guide aware of the difference between being polite and being anti-racist or being polite and being anti-ablist or being polite and being for equality of gender or being polite and being for acceptance of multiple religions - then what's left is for individuals to draw their conclusions of the world from the fiction they read without questioning it.
I learned many things from books, specifically SF. I discovered there were other people like me, women who liked women, via SF. I discovered the possibilities and applications of math and physics and history and politics via SF. And then later in life I either had what I learned challenged or challenged it myself to discover more and discover deeper layers.
But everyone is not me. Everyone is not you. There are individuals who just want a good story and who are not equipped (due to socialization via home, or school) to question things, to wonder about things. The person who wrote the OP review has stated that she didn't see a problem and was ready to accept no First Nations people as the mere background conditions of the story the author wanted to tell.
Engaging with a story fully, be it text or media or opera for that matter is one of the best ways of interacting with information and realizing that it is not static. But it IS NOT something that everyone does either automatically, nor is it something everyone is raised to do.
In fact, it's my personal belief, that half the reason some books are challenged because they bring up issues around gender and sex and sexuality and depression and mental health and drugs and power displacement is because the challengers recognize that many readers are passive readers and the challengers fear that these books will be read and WILL be adding blocks of how the world is in the minds of others.
Must PoC and/or their Allies, raise a fuss with every book like this, for the sake of those passive readers? So they're aware there's controversy and might be brain tickled to discover what said controversy is about? Must everything that causes pain be a learning moment for those who are in the majority?
Because as I've said before, though some people feel that it's all about them and their learning moments. They're not that special - simply because they're ALWAYS having, or demanding, said moments from PoC and others who're just trying to live their lives.
I would much rather people were thinking to start with and NOT releasing books into the world that perpetuate these pains than be part of a daisy-chain of objectors dealing with being called book burners and over-sensitive too PC mambypambies, or whatever the insult of the month is, orcs, nithings, etc...
White people do not believe they need to learn about racism. Yes, this is a broad generalization, but not quite so broad, really. White people tend to believe that the word racist is a highly charged grenade and when it's used against them, it's actually being lobbed in some kind of street warfare and that it is not a matter of someone going "Uhmm.. you've got some privilege on your chin there and some racist thoughts dotting your shirt." And on some occasions. "Pssst. You left the house without pants."
Since learning about racism involves confronting one's internalized racist thoughts, there's a whole lot of avoidance which leads to things like this book, where there was an avoidance of the issues such as the PEOPLE themselves were left out - genocide, it's just too messy.
Thank you for answering my questions.