Fact is, there are lots of reviews written by absolute idiots. i looked at one app that does X, clearly describes that it does X, does X very well, and has a few 5* reviews plus one 1* saying "I thought it does Y, but it doesn't". Well, if it clearly says it does X and you think it does Y, then you deserve the 1* and not the app.
One quite popular audiobook is on iTunes for $22, on Amazon it's two parts each for $14. Guess how many reviews complaining about the iTunes price (yes, $22 is so much more than 2 x $14). Idiots. And how is complaining about the price in a review useful to anyone? I can see the price. It's clearly advertised. You don't have to tell me in the review. Tell me about the product, the things that I cannot see from the product description.