My Amazon book review just got rejected

I just tried to post a review for "An Astronaut's Guide to Life on Earth," and Amazon wouldn't publish it. I have no idea why.

They said to check the review guidelines, but I did, and I can't see what policy I violated. Can you tell me what I did wrong?

Title: I wanted to like this book, but...

Body: I had a hard time reading this book for two reasons:

1) He skips all the good stuff: Just when he might get specific and tell us something interesting, he trails off in generalities. For instance, he writes "A certain personality type that was perfectly acceptable, even stereotypical, in the past--the real hard ass, say--is not wanted on the voyage when it is going to be a long one." (40) End of section. I would love to know what type of person IS wanted on the voyage--what they're looking for, what personality tests are given. But no. That's all we get. He does it again five pages later: "You'll need to master a lot of skills that seem arcane, or that you might never even get to use, or both." However, no specific skills are listed. This book is filled with generalities.

2) His words of wisdom are mundane: I thought this book might have some amazing insights from a man who has had some amazing experiences. Instead, I get flat platitudes that could come from any self-help book at Auntie's Bookstore. "Anticipating problems and figuring out how to solve them is actually the opposite of worrying; it's productive. Likewise, coming up with a plan of action isn't a waste of time if it gives you peace of mind." (72) Another gem: "If you need to make a strong criticism, it's a bad idea to lash out wildly; be surgical, pinpoint the problem rather that attack the person. Never ridicule a colleague, even with an offhand remark, not matter how tempting it is or how hilarious the laugh line. The more senior you are, the greater the impact your flippant comment will have. Don't snap at the people who work with you. When you see red, count to 10." (111) That's not bad advice. Not at all. But I could get that same advice from Bob in personnel. There are few if any deep insights here.
*****
WTF? Did they not accept my review because it was negative? Are they trying to keep negative reviews off Amazon so they can sell more books? I'm truly confused.

POSTSCRIPT (Nov. 17): They reviewed it and accepted it with no explanation as to why it was rejected the first time. I'm still confused.