Why is Reddit not a reliable source of experts?
Well, it's true that it is incomplete from a scientific point of view


Why did you write anything after this sentence?



This is probably a bit flippant. But seriously. It's "incomplete from a scientific point of view", according to your own words. 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. Science isn't about who wrote what; it's about the research. People can publish anonymously in top journals, if they are so inclined and the editors agree.

Not to mention that reddit (and this website) is a popularity contest. Any random person can create an account and upvote everything. Does writing a hilarious answer filled with private jokes make you a great scientist? No. Does it garner a lot of upvotes on reddit? Yes. Do you not see the conflict here? Calling this "peer review" is laughably naive. 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.


  So if you can trust (to a certain degree) ideas from TED talks, Wikipedia, or Stack Exchange, then why should Reddit be an exception?


Just like with TED talks, Wikipedia, StackExchange, and journal articles, you should use your own judgment when determining what to trust and not believe blindly anything that is told to you. It's also true that if something is presented in the form of a funny anecdote on an anonymous website, you should proceed with extreme caution. I don't even understand why it's up for discussion.

PS: I certainly hope that you don't trust blindly anything written by top users here. StackExchange "reputation" is simply a measure of how much time one has wasted on this website. People who have never done any kind of research or teaching have garnered thousands and thousands of points asking braindead questions and parroting well-known talking points without really understanding what they are talking about.