Verified by providing well sourced and reasoned answers. There are PhD contributors but mostly it’s down to providing consistently providing context to an answer and not going off on some fringe tangent. It’s easily the most heavily moderated subreddit.

“Why on reddit” comes up often and the answer has consistently (historically anyway) been that there isn’t really a better long-form public outreach platform at the moment. Blogs are close don’t have the same opportunity for followup questions and definitely don’t have the same “drive-by” effect of just seeing it on the front page.