Have you ever seen a riot? Those are not pretty: property destroyed, things on fire, people hurt, sheer pandemonium. And that's just with humans: imagine how it would be with a race that are many times stronger, tougher, and with a known history of responding to insult with injury.
And don't bother using the argument of "oh, they're oni, they fight all the time, it'll just let them loose steam". No, it won't. It's not a random bar fight where they just beat up on each other, maybe break a few walls, but everything turns out well in the end. They won't be fighting each other, mostly, they will be concentrating on the focus of their problems: Deva K. Her home will be wrecked, and then they'll march out, looking for her, destroying more things (including possibly our precious bar, which we now don't really have any resources to pay for the repairs, not without trying to set up some sort of trade), and running into more people, either adding them to their riot or taking them out.
What's worse is that we don't know if there'll be any sort of policing force to keep them contained or even disperse them: we know K is not here, and we have no idea where Yuugi is.
So, when the riot ends, one of the first things K will try to do is figure out just how the riot started, and it will come back to us, thanks to us discussing the whole rabbit issue with several of the oni, and the like. You think K will be impressed with us after that? You think she'll really want to listen to us about the gem barter scheme?
And speaking of which, the riot forming to go after K is the better solution: what if they decide to teach those rabbits a lesson? Congratulations, Nue, you've just started a war between the oni and everyone aboveground.
What we need to do now is at least attempt crowd control: if it works, then the oni may disperse, and K's lackey will be grateful to us. If it doesn't, well, we'll at least have that deniability that you've been wanting so much.