I don't think they have interest in fake reviews. But they might have an interest in not having a lot of products which don't sell at all because of mostly bad

I don't think they have interest in fake reviews. But they might have an interest in not having a lot of products which don't sell at all because of mostly bad reviews (they are the Nr1 platforms for cheap "Chinese" products, they would lose a lot of sellers if they are no longer suited for selling low quality products) . They also might have some interest into a erosion of trust into non "sold by Amazon", "shipped by Amazone" and "Amazone Choice" products. But that supper speculative.