I'm reading a ton of reviews from 2014 to write up this year's top reviews of 2014 along with wiki editors. See Anime Vice's Review archive 2014. I notice some reviews of shows with mixed reactions get thumbs up and down. It's more of a suggestion. I won't change many folks' thoughts on how they read and recommend/reject a review. This is just my opinion on the matter.
I have seen reviews that aren't reviews, more like rants or short thoughts on what they like instead of a complete article that analyzes pros and cons as well as stating their opinion. I never rejected them. Left comments as suggestions on how to improve. The trend I see is users rejecting reviews because they disagree with the reviewer based on their tastes rather than on how they review the show. Everyone in any fandom of a media have different tastes. The purpose of reviews I see is seeing the reviewer's style and thoughts whether it matches with you. You know whether to give this anime or manga a try. I know folks have different outlooks on what a review is supposed to do.
That's the hard thing about reviews for newcomers. They worked hard on something. A little positive feedback can help them feel good about their work. Everyone, mods and users, we want to encourage reviews because it's part of the site just like blogging, wiki, RPGing, battle, etc. This is a unique community.
Feel free to agree or disagree. I would love to hear your thoughts.