Earlier quoted context omitted.
To be fair, "bombing" review sites is entirely a market action. The market works through information. The most common way that information is disseminated is through prices, but that doesn't mean it is the only way. Reviews, etc, allow one to more accurately decide how to value something.
You're playing games with the definition of a "review". People looking for book reviews are in virtually all cases looking for information about the content of the book. I can't win the nerd argument with you that there is no information whatsoever in the review bombs, so I won't bother; I'll just rest my case that the information is below the noise threshold, and adds so much extra noise as to make the reviews usele…
If a review has zero information, then I agree with you that it is absolutely worthless and should be removed. However, if a review clearly states why it is scored the way it is, then it doesn't matter if it is purely about the content of a book or not. I have seen plenty of reviews which indicated shoddy binding... would you say these are worthless as well?