I reported this to Amazon via Twitter on July the 18th [2] (Sorry, German).
I checked yesterday and despite Amazon promising to look into this, all reviews where still there. So I tweeted to them again and, at last, they're deleted today.
But why is this not detected automatically? 378 verified 'customers' that all review the product, with five stars, on the same day?? What are the chances?
And the language of the reviews was also so similar that even a Markov model could be used to detect they must be from the same person (or bot). No machine learning needed.
[1] https://www.amazon.de/MAOFINE-MacBook-Adapter-Charger-Replac... [2] https://twitter.com/virtualritz/status/1019741791422173185