Do you tell potential employers about every major mistake you've made in previous jobs or about the times you've slacked off or skipped out for one reason or another? If not, then you're not making it clear that your resume, cover letter, and job interviews aren't fully representative of your prior work.
Do you think that the interviewers think it is? Do you think that if you read a persons resume that it would be a fair assessment of their past work history and experience?
Or would you accept that everybody that submits a resume is obviously biased and reporting on themselves is not a full and complete history. Since they have to include references and contact info for their previous jobs it seems that they are by default not trusted to be a complete and balanced source by themselves. So your example stands as it's own opposition. People do not tell about themselves when trying to impress someone to get a job and everybody knows it and expects no less than embellishment. Hence they ask for outside verification as well.
How about stuff that you're trying to sell like a car or a home?
If you are trying to sell a car or a home there are third parties that are expected to inspect these objects to ensure your statements are true, it's not expected that you are an expert in all the areas that are important in these cases. You are also judged on your trustworthiness in these cases. It's not the same as if the person was to filter the results of a termite inspection and only report the good parts, or if they altered the carfax report on the car. That's why there are these third party services, because people are not expected to be unbiased in their account of their own worth or the products they are trying to sell.
Companies are a different matter.
There are quite a few laws in place that people trust are being obeyed. It is illegal to advertise falsely that your product cures a disease or treats an illness.
It is illegal to advertise a product of some value and then once the customer is ready to purchase it, switch to selling them an inferior product. (as a practice)
There are many other laws about advertising because the business world needs trust to operate. And while it doesn't create the level playing field it means to, it does put into the minds of the populous that they can trust to some extent the claims of retailers. There is a big difference that may not be in the front of their minds though. That there is a big difference between an acknowledged advertisement on TV and a retailers own Website.
To advertise on TV or even place banners through Google adds, the retailer must meet certain criteria. Small print, disclaimers, relevant details that go with their claims of a certain product. That's why we all see things like, "results not typical" "your results may vary" and "see retailer for details". These things don't help sales but they are required when advertising a claim. If they claim something without so much as an asterisk and it is not true, they could be in trouble. But here's the problem. If they have a Website that promotes their product and only has the most glowing reviews but does not claim that the reviews are representative or inclusive or even unpaid. It's not a claim that's false. They don't have to say that the reviews are anything, they could be just marketing people typing the company agenda. And we assume they are real reviews since they allow us to submit them as well. There are no laws in this area. they can delete your review and unless they use your name and change the words, it's within the law. It's a problem with what we expect in one area not applying to another. Like copyright and patents, most people don't know where one stops and the other begins. And I think that's the fault of the ones who are in change of the laws. We should learn them, but we should also not be expected to have law degrees to do so. Like anything that effects us all so much, there should be a brief attached that explains as succinctly as possible the meat of the laws in these areas and it should be taught on such a widespread basis that everyone could spot a company trying to fool them in this manner. But that's only hopeful thinking I know.
And to the GP:
Don't know if it's illegal or not but it should be. They are misrepresenting the site as presenting all reviews, not just ones that they approve. That's fraud with material financial consequences.
Unless it says that these are all reviews, it's your assumption. And that's not illegal for them, just irresponsible of you.
Do you believe what you see in an infomercial to be the actual results of a fair representation of users?
Or do you notice the small print of "dramatization", "up to" or "actors" that are required of these claims in the advertisements by law.
Without a claim that these are all the reviews submitted, they don't need to tell you that they aren't.
So while I see no obviously illegal act, I see a loss of credibility. And that's the open market at work. If I find out who this company is, I will simply not buy their product based on what they, or their reviews, say.