Why are those reviews included at all if they weren't "verified purchases"? I guess there's some utility in it - you already own product X and want to let people know about something (positive or negative) but... this blatant sabotage from obvious non-customers/users is crazy.
You would pay your manipulators to leave verified purchases. In the black market for manipulative reviews that comes at a premium. You can also get similar effects with unverified reviews on some product types (consumables, beauty products, etc.)
It's not non obvious if you bribe someone who uses an American shipping address to do it.
