Well, the short answer is that there is no accounting for taste. These ratings are given by the members themselves, and some are gonna always give ratings that you might disagree with.
I never paid much attention to this myself. So I decided to play around with it a bit to see how it works.
You are right, BTW, your latest IS a work of art.....Soooo.... in the interest of "testing purposes only".......
..... I went and gave you a vote of 5 stars. Then went and tried to do it again, to see if I could "game" the system. Nope. I could not do it.
So it doesn't look like anyone can do anything like vote multiple times for reviews done by themselves or their buds. You can only vote one time.
Realize, though, that it only takes ONE vote to show a rating next to a review. So even if only one person votes for it, it can look like it is a "5 star" review, even if it is a POS by the standards of most people. But if you hover your cursor over the stars, it will give you a summary of the number of votes.