Yeah, based on the really awful cases of my wife's family, the problem exists between the keyboard and the chair. When faced with fact-checking or truth that refutes their insane conspiracies, they double down and call the fact-checkers or truth-tellers liars and invent even more insane conspiracies about how the "real truth" (read: heinous virulent BS) is being suppressed because the clickbait article about how "liberals are planning to euthanize all whites!" now has a disclaimer under it that says "this claim is disputed" (a caveat so weak that it'd be almost funny if it weren't depressing how many psychos eat up the totally-untrue headline).
It's the only thing that is starting to turn them on Fox News for example; though they still watch it religiously, the fact that the most feeble, CYA-grade questions were asked during their brief "news" segment that slightly challenged Trump's baseless "stolen election" narrative now means that they've moved from "only Fox is telling the truth" to "well, I don't like everything they say, bit they do a good job, like Tucker Carlson" (who is probably the most prominent disinformation propagandist on the whole festering network). In response, they've turned to just any old 2-hour-old "freedom eagle dot biz" site as their "real true sources", because Fox had a brief lapse of allegiance to the Trump cult.
You can't fix that with an RFC, a law, or a moderation policy because they've rejected any possibility of accepting the truth. They're thoroughly deceived, most especially by themselves, and any attempt to un-deceive them is seen as a sinister plot. They refuse the truth outright because it's not what they want to believe.
You can't fix it by shutting down or "breaking up" the site where they go to get their much-desired disinformation, because there's always another con artist with a Squarespace or WordPress license who'll gladly capitalize on having less competition in the "cult propaganda dissemination warehouse" market (like OANN capitalizing on Trump's brief lashing out at Fox, or Parler springing up because Republicans started getting "this might not be true" disclaimers on their lies).
I've always seen "you can't fix stupid" as a harsh redneck insult, but I'm starting to believe a slight variant on it: "you can't fix willfully-ignorant." You'd have to change their thought patterns and their habits and often their motivations, and that kind of change doesn't come from outside but from the person themselves.