I don't think I follow. Who else would start a list if not a reader?
It could be anyone; someone who wants attention, someone who has a lot of free time on their hands, etc.
I think it is an addicted caller who is upset that some of their favorites weren't all 5 starred and doesn't like that one or more of their readers were what they viewed as trash talked, either here or elsewhere.
I work with clients all day long and many have the group think approach that this writer took. It's very common of clients of any profession to slap a label on a profession. They are all in it for the money, can't trust a ___, etc. This person did it in reverse. People in a profession slap different labels on their clients. It usually has to do with being on time, keeping appointments, being truthful, paperwork organization, paying their bill and not on the thought process as a whole of everyone we see. I don't know what everyone I see is thinking. That's insane.
Everyone is an individual, not cattle. They have feelings. Some are deeply troubled or mentally ill. Some will never be happy even though the best that could possibly be done was what was done for them. You do the best anyone could have, or even would have, and you get a shitty Yelp review. Basically, so what. Move on. Who gives a shit about 5 stars. If 1,000 people loved you, will a few 1 stars matter? No. When they come back to you again, and they almost always do, you decline to assist them again. Most people are too busy making money to spend all kinds of time making up stupid lists, running deep Google searches and making blog posts with nonsensical ratings of clients.