If that's the case, then there's verifiable material you can cite in support of your argument, rather than relying on original research.  It doesn't matter if everyone on the planet agrees with your argument, if you can't verify it or cite it, it doesn't belong here.  If you want to argue that Poster X is libellous, you'll pretty much need to cite a legal opinion or judgement, or say that Politician Y described the poster as libellous.  Our own opinions, no matter how widely shared, are insufficient. This article, unfortunately, is not a very good example of how these principles should operate.