A review system such as Amazon's is never going to be particularly trustworthy. I don't sweat it too much. I don't dwell on the reviews in the first place--and even when I do look at them, it's painfully apparent when there's a concerted agenda (pro or con) going on to all but the most oblivious of observers.
I'm not sure when we started believing that readers were entitled to an unbiased, honest appraisal of the quality of every single book in existence--before they read it--in the first place. If it intrigues you; download the free sample. If it still intrigues you after reading the sample; consider buying it. But let's stop pretending that Amazon's review system can ever evolve into anything particularly useful (or even relevant). I've enjoyed many a book in the past that "respected" reviewers all ganged up against too.