I'm not a lawyer @Sarah3260 but if you want your Yelp review taken down I suspect that might be your only recourse. Or you could just reply briefly, factually, diplomatically to his review so it was clear to other users what is going on.
I dont' agree with this hosts behaviour, but I suspect it's going to be as hard for you to remove his review from Yelp and it is for him to remove your review from airbnb.
Personally I would have tried to be a little more diplomatic in my reivew of this host, but that's not my business and I didnt' stay there, not have your experience.
I can certainly understand why airbnb CS is not going to get involved in this however.
good luck sorting this out and keep us posted