> But as you said, there are plenty of people who give 1-stars for almost no reason.

I've seen studies that seen that (honest) ratings in number/star systems are strongly culturally correlated, and that American culture strongly favors giving the highest rating unless there are out-of-ordinary reasons to go negative, while some Asian cultures strongly favor giving middle to low ratings unless there is out-of-ordinary reasons to go positive.

So simple cultural correlations in awareness of and use of a particular brand of a product could result in very different review results with exactly the same customer satisfaction profile.