Are the researchers really sure that the moderators on popular subreddits are really 'unpaid'? Recall the whole editor-for-hire scandals that plagued Wikipedia? A PR firm interested in controlling the direction of discussion on Reddit or Wikipedia has a large vested interest in having their paid staff members act as moderators for popular subreddits in order to control the direction of discussion and spike stories that don't fit their desired narrative, whether that be on behalf of a government or a corporation or an individual. This is hardly a new problem, see this story from 2012:

https://www.cnet.com/tech/services-and-software/wikipedia-ho...

> "Perhaps the paid-PR scandal is a coming of age for Wikipedia in the era of SEO shills, and the public's increasing awareness about powerful corners of the Internet -- and how subject they can be to the interests of close-knit friends and business associates. In this light, a Web site as insanely valuable as Wikipedia will always attract gaming for promotion."

This is hardly just the moderators on Reddit, there's also the armies of upvote and downvote bots that can be deployed to push a story to the top or bury it, ditto with comments, and then there's things like the outright bans for anyone raising particularly controversial topics (bans for mentioning the Wuhan lab leak on Reddit is one of the more blatant ones, for example).

All in all, social media is not what anyone in their right mind would call a 'reliable unbiased information source'.