Reposting by comment from your post on omnilibrium:

You failed to address, or even acknowledge the question, of who fact-checks the fact-checkers. For example, you mention PolitiFact, it has a acquired a reputation for downplaying some politicians lies, and in some cases even outright classifying true statements as lies by others.

In general, this proposal is just silly. After all the media is supposed to fack-check politicians but it is rather notorious for its own biases and even occasional lies. Why would we expect self-proclaimed fact-checkers to be any better?

Also, judging by the upvotes this post has recieved and the rest of the comments, it appears even most LWers will accept someone's claim to be stating facts without question.