DealerRater is in business for dealers, not consumers. Sort of a Reputation Defender (reputation.com) for car dealers. They attempt to validate reviews, and let dealers harass you when you post something negative. When the collect positive reviews (real or bogus?) they can offer a scrolling feed for dealers to imbed on their web sites. The negative reviews are suppressed.
If dealers were concerned about negative reviews, they should be investing their money and effort into customer satisfaction (prevent bad reviews) instead of suppressing (censorship) of negative reviews. I know some bad reviews are from hotheads that may actually be in the wrong, but a business that helps harass people who've been legitimately mistreated is flat out wrong. DealerRater.com and Reputation.com are all about flooding the internet with redundant good reviews and attempting to flood out the bad reviews. In the end, neither can be trusted.
It's back to word-of-mouth, I guess.