Personally, I don't think Google should be obliged to promote all kind of crappy 2nd rate products out there. I hate Yelp. They are greedy bastards who have cornered up huge content entirely contributed by volunteers. They are the ones wanting to monopolize market in this area and avoid having Google as player here. They are the ones who want big price for their theft from millions of hours donated by volunteers. Yelp reviews and ratings should be free and in open domain by vary nature of how it was created (and so should be Amazon's review - but at least they are not entirely volunteers driven website). On the top of this, Yelp has remained mostly stagnant waiting for their big payout day. I don't consider them good for users or internet or industry. So for me this is pick between the worse evil.
The debate is so very similar to IE on Windows, however. Should Microsoft be prevented from creating better[1] browser and not allowed to complete with Netscape? Should they be prevented from putting their integrated polished experience in front and center that benefits the customers? One can say that suing Microsoft actually worked out best overall for industry. I'm not too sure how alternate world would have looked like. History certainly rhymes here.
[1] You can say whatever about IE's lack of implementing proper standards but it was the fastest browser in its day. It was truly free no strings attached (as long as you are on Windows) and it advanced many things, for example, it was the first browser to implement CSS, XML parsing and tons of functionality that is now part of HTML5 standards.