Well, yes. Because that's the way things work: the burden of proof lies on the person making the claim.
I suppose I could click the button in the quotes that takes you to the original post, leading all the way back to the first in this chain, where a GWCarver makes the claim that Fox News shows liberal viewpoints in a serious manner. That the negative claim you want to be proven is the null hypothesis to this original claim.
Or I could not do your work for you. That sounds easier.
