Looking through both snopes and Rationalwiki is an interesting exercise in that both are very similar: they are both patronizing and authoritative in their patriarchal approach in telling people what to believe and how to believe it. Rationalwiki is the worse of the two offenders in that it proclaims to be against pseudo-science and conspiracy theories, and yet its approach isn't scientific itself.
Like snopes, it gained legitimacy by picking on the obvious trash. It is akin to if I went on a tear to say how The News of the World is fake news. Calling out InfoWars doesn't make you an expert in weeding out truth from lies. It takes a deeper understanding than that.
But people want fast and easy answers that you can crib from a web site with a point and a click. You do not want to look foolish at the dinner party as you pretend you know something serious about politics: so you scour web sites to tell you what to think about various outlets.
In structure, these sites are relics of a bygone era that remind me of old PSA announcements that had a stern male voice tell you that in case of an atomic bomb attack, to hide under your desk in the classroom. There is nothing remotely rational about the process. These are a serious of cheats and hacks that do not actually inform.
Critical and independent thought requires independently verifying information. As someone who worked as a journalist, I can tell you right now that I used to verify information from both "credible" and "dubious" sources, and often, what I found was the so-called credible ones made mistakes or flat-out lied or were wrong, sometimes more than the dubious ones. And as for the dubious ones, very often, there was spin and lies, but other times, the information checked out -- or at least one vital part turned out to be true -- the spin or narrative was wrong, but it will still worth my while to listen.
Sites like these require appeal to authority: they expect to be the authority you appeal to without question, making them Patriarchal -- and flawed. It's puffing, of course, but also bluffing. They also appeal to authority themselves to make assessments of the veracity of various organizations. It is not as definitive as it first appears.
Journalists often crib from snopes and its ilk when trying to hedge their bets. The Washington Post cribbed from a site proclaiming to be an expert is spotting fake news. Newsweek had to retract a story as it relied on another such web site to make an outrageous claim.
These sites are a way to shut down debate and empirical investigation: you run to mommy and daddy to tell you who is right and who is wrong. There are no tools to make determinations for yourself.
These sites run on opinion, not fact, and just because one claims they are fighting against "pseudo-science" does not mean their ways are scientific by default. There are no laws, regulations, or standards governing these warehouses of decrees. Slapping a label of "conspiracy theorist" to anyone you do not like is hardly helpful.
We do need better vetting. We need standards. We need facts, but not through a filter of arrogance that is too crude and obtuse to be of value -- or find grains of truth, even in some of the unlikeliest of places.