RationalWiki is about as reliable as the diary of an average middle school kid; I wouldn’t outright dismiss everything they say as baloney, but expect lots of bias and factual inaccuracies.
It was created by a group of immature adults who enjoyed vandalizing other wikis, like Conservapedia and Wikipedia. They basically created RationalWiki to publish what the other wikis wouldn’t allow them to publish. For the naysayers, go look up RationalWiki on Wikipedia and notice the LA Times reference. As an example of the maturity of the contributors there, how I first discovered RationalWiki and Conservapedia is from one of RW’s administrators contacting Wikipedia vandals on their user talk pages to suggest vandalizing Conservapedia instead; I won’t call him out in this forum, but he has been community banned from Wikipedia because of his shenanigans. The problem with taking RationalWiki seriously is I don’t think it was ever really intended to be taken seriously, hence why many of the articles are loaded with snark and the users frequently engage in immature actions like block wars (where the admins block each other with ridiculous accusations as the block reason, like “keelhauled for being unpirate”).
The site has a very high turnover of editors. I don’t think a single person from the early days is very active on the site anymore unless they are using a new identity. A significant number of the current editors are minors (which I discovered last year during board member elections, when several people turned down nominations due to being under 18), and I’d say most of the ones who aren’t are likely young adults, probably not even old enough to drink in most US states, and almost certainly not older than 30. So basically, we can assume that a lot of the opinions and original research on the site is just the rantings of rebellious high school students and college students. A lot of Wikipedia content is also created by high school students and college students, but they are expected to base what they say on reliable sources, unlike RationalWiki where they rant about how weird they think certain people are.
So if you are wondering what left-wing youth like David Hogg (and not all youngsters are leftists, by the way) might think of something, go to RationalWiki and you’ll get an idea, but otherwise, I wouldn’t recommend the site for anything more than entertainment purposes.