Yelp is bad. Google is bad. Or more precisely, both are amoral, and responding rationally to the incentives of the internet. The traditional anti-trust sense you mention doesn't take network effects into account. If you ask me, network effects cause the landscape of the internet to inevitably trend towards oligopoly.
This explains why the strategy of most startups amounts to "Growth at all costs, until you're the only game in town" (The model of Facebook, Google, Amazon, and every wannabe unicorn running at a huge loss to investors)
Should a different case (maybe a class action) be brought against Yelp for abusing its position and momentum to force restaurants into joining the platform? Probably yes, but it would be a different case which, albeit rightful, has nothing to do with the Yelp-Google case.
Yelp sues google for monopolistic practice. Restaurant federations sue yelp. We sue fb for giving us the willies. The lawyers do very well and there's a legal bubble. Peter Thiel automates lawyers, funded by google who by 2026 are sitting on the largest horde of cash ever stashed but technically bankrupt, pending legal appeals and fully tallied lawyer bills. Legal event horizon in 3.. 2.. shoes.
I don't think I speaking besides the issue (apart from the obvious bits). Are either of these companies accused of anything, formally? Murder may be a bit strong.
In a wider more pedestrian sense, there is a some kettle-pot-black involved here, at least in my opinion.
Yelp's a little monopolistic middle man. Everyone reads and writes reviews on Yelp because everyone reads and writes reviews on Yelp. Market dominance today is the main ingredient for dominance tomorrow. Everyone uses Google search, maps, phones etc. Google gets all the data & ad revenue. They use this to maintain their dominance.
Pick your euphemism for this position: momentum, network effects, buffet's moat, thiel's-monopoly, dominance, viral feedback loops.... Whatever you call it, a restaurant can't opt out of yelp, just like a website can't opt out of google. Their rules are the rules. There is no option B.
A downstream company can be harmed when Google competes direct (AKA the terror of 2006), when they redirect traffic to alternative web pages or disrupts market dominance downstream, intentionally or otherwise.
This is like Yelp's relationship with restaurants. Yelp can stop sending a restaurant customers. Google can stop sending Yelp users. There are no "market dynamics," no "invisible hands," price signals or whatnot. There is no "market" to impose discipline in the way the laissez-faire idealization does on paper.
So... I'm kind of torn. I want to see far more complaints, cases & legislation targeting market dominance, size and monopoly. On the other hand, the hypocrisy...