[low_key]

I've left negative reviews and they tend to get removed.

I was once even warned by Amazon that my account could be deactivated for violation of the ToS after posting a review that pointed out all of the other fake reviews on a particular product. Apparently the ToS allow fake reviews and disallow shining a light on it.

[bombela]

Yep, same experience here. Everytime I reported, my updated review was deleted.

[FeistySkink]

Amazon Vine is a thing, so of course they encourage fake reviews of free products.