book reviews

Amazon not accepting (positive) responses for reviews on Griffin's new book

I am trying to record my approval of reviews posted on Amazon of David Ray Griffin's new book on Osama Bin Laden, Osama Bin Laden: Dead or Alive?. I get the message indicating that my comment has been processed, but the counters do not increment. Elizabeth Woodworth has reported to me that others are telling her the same thing. Can some others try this and see if they get the same results? The link is

http://www.amazon.com/Osama-Bin-Laden-Dead-Alive/product-reviews/1566567831/ref=sr_1_1_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

Here is the interaction:

The question after each review is: "Was this review helpful to you?"
The response button I choose for each good review is "Yes"
The Amazon response is "Thanks for your feedback"
The counter at the top of the review does not increment.

Is this a computer glitch, a mis-understanding of what is supposed to happen, or someone gaming Amazon to keep favorable review counts down?

Regard
Michael Zimmer
http://www.TheProgressiveMind.info