It's not Yelp directly, it's their outside sales contractors. Anyone who manages the online presence of a small business can contribute corroboratory anecdotes, including me. Yelp encourages this behavior from their contractors.

I'm sorry that no one has formally studied Yelp's shady business practices, because that leaves us without data you find worthy of consumption. Maybe an enterprising law firm will change that once they smell enough blood in the water.

Until then, consider that swaying someone's opinion on Yelp using their own PR resources is a complete waste of everyone's time.