It looks like the rejection email was from Amazon KDP (Kindle Direct Publishing). So Amazon isn't refusing to sell the book, just refusing to publish it, from m

It looks like the rejection email was from Amazon KDP (Kindle Direct Publishing). So Amazon isn't refusing to sell the book, just refusing to publish it, from my understanding. That seems like a much less significant issue if that is the case - there are lots of alternative publishers to Amazon, so it is less concerning if they have more strict standards, since you could just go through another publisher and sell on Amazon through them.