The other top 50 reviewers (on a few randomly-clicked items) are doing the same thing, but put the advisory about being supplied with a free item at the end of the review. These reviews come off as being little more than descriptions of the product, some mild inoffensive personal opinion, and a 5-star rating unless something is very wrong with the product.
Annoying, but what else can one expect? If there's a reward out there for being in an exclusive category, some people will try to game it, and in the case of Amazon the reward appears to be that people will send you free stuff. Lots and lots of free stuff, which I presume you can make some money by selling or trading away.
As for gaming the system for own benefit -- obviously people are getting some free stuff, but is it as tempting as it sounds? I don't know. A few years ago I was invited by Amazon to join their UK Vine programme. I was obviously very happy to do so and get things for free just to write a review. After a few (two or three) months I stopped asking for items to review for the following reasons:
1. Most of the non-book stuff I got were things I wouldn't care about unless they were for free. And when I did get something I did like (e.g. headphones) I wasn't impressed with the quality of the product.
2. Some of the books I reviewed were really not that good, and were a proof-read copy filled with typos.
3. With Amazon Vine, you aren't supposed to sell (or give, or throw) the items you receive. I realised that I will quickly fill my house with things I didn't want and didn't like.
4. Writing a review about something I didn't care at all about was a tedious job. I used to like writing reviews about things I felt I had something to say about before joining Vine. Not so much anymore.
Since this person is not part of the Vine programme, I guess only #3 doesn't apply to them, but I still don't envy anyone who makes their living by testing a set of spatulas and then sell it on Ebay or wherever.
So, since I think they're providing useful information in the reviews (and maybe review stuff that other people wouldn't bother reviewing), and since I don't envy them, I'm not really annoyed by them. I haven't reviewed the other top 50 reviewers, but I suspect that I'd feel more or less the same about all of them.
I haven't reviewed the other top 50 reviewers
LOL startup opportunity
Edit - grammar