I used to occasionally review products I didn't purchase from amazon but locally, usually very positive but maybe a few somewhat negative, and they were published after a short lapse. The last time I tried to review an item and not be a verified purchaser, I was blocked. That was within the past year or so.
I think people can still comment under a particular review; some got quite heated and lengthy in the past. I know the book I commented on I had not purchased and didn't intend to. It seems to happen very rarely now, if at all.
I didn't want to risk my generally favorable, I think, reputation by playing with the stars and faking a review as I have no desire to purchase the book. There are usually enough details getting out that it's not worth reading the entire book, don't like kindle and don't read but a very few books any more.
I’m glad they require people to have bought the item they are reviewing. There was a time when I saw quite a few reviews that worked proper English, all the written similarly. It’s annoying to not be able to trust the reviews. That’s one of the best features of Amazon.
I suppose political books get a lot on both sides.
but I’d really like to know what’s behind Amazon not allowing a verified buyer to leave any review they want.