I looked at the book reviews yesterday. Tons of one star review, but if you sorted by verified purchases the vast majority of them disappeared. Honestly, to minimize gaming Amazon might just have to start restricting reviews to verified purchases, even though that has its own set of drawbacks.
This is The Guardian just now realizing (or, maybe, just about to realize) that Amazon has to do stuff like this with most products, because online reviews are supremely game-able.
It's easy to find certain products whose reviews are illegitimate for one-off social or political reasons. A lot harder to fix the fake reviews that prop up a bad product or vice versa.