You stated it as fact, so it's better if it's backed up. If you're stating it as opinion, then that's fine, and you have no need to back it up, though it helps. But to state it as fact, then say that evidence is "impossible to prove" is a pretty weak argument.
I just never get over the irony of a fan on his team's message board calling out a TV network for bias
In my opinion the Reds have gotten plenty of coverage as they've begun to win, which is how it is for most teams, and, dare I say, how it should be.