Eh?
The 'strawman' argument as far as I can tell, is being maintained by yourself. And you've got it mixed up to boot. To clarify;
Most people don't post reviews, especially if the experience was positive/uneventful. It is widely accepted in business that negative reviews are over-represented as people are more likely to post following a bad experience (This thread is a case in point).
Your observation on percentages may be more accurate however. But a 10% negative review probably translates into 0.5% of total sales/customers. In the case of a very large company with a large high street presence, it is likely to be considerably less than that even.