Banning products is not something you would do every day. It's the kind of thing you do randomly in large swaths so "false flag" operations are likely to hurt you as help and are not free.

Banning reviews: No it's not legitimate. Customer reviews are useful specifically because they are by people that thought the service might be worth while. If you can't afford a 911 or don't like the way it looks then your opinion is not meaningful.

From amazon's perspective review integrity is expensive but so is giving up. As a customer it feels like they gave up a while ago which opens them up to competitors.

EX: Newegg is where you buy video cards not Amazon.