This doesn't preclude the possibility that one side's media tells the truth more accurately than the other's.
Well, we can at least say that one side in more sophisticated in how they present their truth, but I'm not sure that makes it any more truthful.
Of course, but that’s completely orthogonal. Nobody believes their own side’s media because it’s less easy to debunk; people instead believe that media because it’s the media from their own side, and as such tells people on that side what they want to hear and believe.