The subject of plagiarising book reviews has come up a few places. As is often the case, it takes Dear Author raising the issue for me to actually stop and think about it.
And when I stop and think about it, I'm stunned.
To me, a review is part of my engagement with a book. It's an extension of my reading experience, a way to share that joy with others. To steal (plagiarise) a review is like wearing someone else's unwashed underwear--icky in a major way.
A book review is a window into another reader's experience with a book. It's something private that they've chosen to share. Why would you want to pass off someone else's experience as your own?