Is a book refund a "bribe"?

So here's an experience I had with an Amazon used book seller named "Booxygen". I had ordered a book from him and the book arrived on time. However the book's spine was detached about halfway down the middle. Problems with the spine constitute probably the most serious problems you can encounter with a book. So I wrote a lukewarm review on Amazon in the "seller feedback" section complaining about the spine.

About two days later I get an email from Booxygen. While they apologize for the problem, they also make me an intriguing offer. They say that they will refund the price of the book if I take back my negative review and either write a positive review or no review at all.

Now I know this sounds reasonable and is probably the norm for most book sellers, but in my view, such an offer clearly constitutes a "bribe" for a simple reason. Reviews are supposed to attest to the quality of a particular bookseller. Consider what happens if I accept Booxygen's offer. While my money is refunded, because I don't write a negative review, future buyers like me who are planning to buy from Booxygen never get to know that I was shipped a defective item. The whole purpose of reviews is to accurately represent the quality of a bookseller's service, warts and all. A failure to write an unfavorable review or the misrepresentation of such a review clearly misleads future buyers.

Thus, while it sounded reasonable, I regarded Booxygen's offer as a bribe. My reply somehow got buried in the drafts section of my email. I discovered it three months later and emailed Booxygen a deal which to me sounds much more honest; mail me a good copy of the same book and I will gladly take back my review and write a new favorable review for the book. Regrettably, Booxygen sent me a very rude reply saying that they refuse my suggestion and that I should not do business with them again. I am glad they said this themselves because I am pretty sure I won't feel the need to buy from them again. In addition I am quite sure I am not going to accept such a bribe from other booksellers; if you want good reviews, sell me good quality products. It's that simple.