Reddit users don't go through the painful process of checking all the details of a comment before deciding to click on that arrow button. Do you not see the conflict here? Calling this "peer review" is laughably naive. Does it garner a lot of upvotes on reddit? Yes. Does writing a hilarious answer filled with private jokes make you a great scientist? No. Any random person can create an account and upvote everything. Not to mention that reddit (and this website) is a popularity contest. People can publish anonymously in top journals, if they are so inclined and the editors agree. Science isn't about who wrote what it's about the research.
Why do you need anything further to justify the fact that reddit is on a completely different level than academic journals? You are focusing too much on the identity of the writer, when you should have been focusing on the actual content. It's "incomplete from a scientific point of view", according to your own words. Why did you write anything after this sentence? Well, it's true that it is incomplete from a scientific point of view When should we ask questions on Reddit? (quite a misleading title in this context, but anyway).Are there instances where citing Wikipedia is allowed?.Are TED presentations academically credible?.Any random person can create accounts, upvote, and write hilarious comments, but only those who actually have the knowledge can write serious ones and show the holes in my knowledge. Yes, all of the points are applicable in a generic subreddit, but I'm talking about subs that the fact one is in there means that they must have a certain level of knowledge, or else they can't never find out the sub. PS: I think the keyword specialized subreddit hasn't been implemented enough in the answers. So if you can trust (to a certain degree) ideas from TED talks, Wikipedia, or Stack Exchange, then why should Reddit be an exception? Saying a frequent redditor is not necessarily an expert is like saying top users in Academia Stack Exchange are not necessarily academics I think. It also has the same peer review mechanism like Stack Exchange, and you can always visit users' profiles to evaluate their expertise.
Well, it's true that it is incomplete from a scientific point of view, but most active users in a specialized subreddit likely know what they are talking about. Some people say that you should take for granted for opinions on Reddit, because comparing it to academic journals is like comparing kindergarten to university.