There is zero physical evidence that Yelp does or ever did this. The only thing that Yelp ever did was move one positive review to the top of the page for advertisers, and I'm pretty sure they abandoned that practice a long time ago.
It's pretty obvious to me that unsophisticated business owners are simply drawing false inferences when they receive a sales call and then receive a negative review. Confirmation bias at work.
Here's an old Hacker News comment that seems to me to probably be close to reality: https://news.ycombinator.com/item?id=1149078
One example: https://www.youtube.com/watch?v=8CIGKxLcoso
That's evidence that Yelp practices extortion?
However, this video very clearly shows a family who incorrectly blames the business owner for one of their members losing a job. Yelp fired them, as they should have.
https://youtu.be/BHEbVh3Yhrw?t=442 may be better, as he talks with two of the people behind the movie Billion Dollar Bully. (I didn't re-watch it completely, as I don't want to get myself wrapped back up in his world.)
As it notes in https://slate.com/technology/2019/06/billion-dollar-bully-do... and the above, if Yelp's culture means that employees are getting away with it, and sharing that, and tend to work with people who aren't web-savvy, there's certainly the opportunity for certain individuals within the company to give the company a bad name.
For-profit businesses, especially ones that want everyone to use them, generally don't like to talk about the fact that some part of why they exist is for the money and/or they have stakeholders that want to see a return on their investment.
It's also possible that Yelp has since gotten better, and they're still fighting off the old perspectives. Not OP so not sure where their evidence came from.
(I personally rarely use Yelp, don't have an account, and prefer the reviews built into Google Maps since that's my navigation app of choice. I didn't know about issues with Yelp until I was subscribed about the above, and after unsubscribing numerous months ago haven't heard anything else about Yelp until now.)
i don't see what yelp had to do with it.