I would much rather have a variety of perspectives than a coherent narrative.

You learn more that way.

My observations don't suggest that principle holds true for the general poplulation. I fear too many people lack either sufficient knowledge or sufficient critical thinking to independently determine whether strongly-made claims successfully fact-check.

Lacking that ability, consensus of the commons is more likely to be correct than fringe opinion and can back-stop that missing ability.

Much of the Internet-connected world is currently running a fascinating experiment on itself regarding whether a public exposed to a fire-hose of unmodulated opinion can grow in aggregate wisdom or will be dissolved by gibbering foolishness. The results of this experiment are not yet determined.

You make interesting points.

My observations suggest that human beings above 18 are adults and can think for themselves.

"Benevolent" attempts at manipulating the crowds by people who think they are wiser or more knowledgeable...leads to more harm than good.

If by manipulation you mean discourse, then there's a whole history of more knowledgeable people sharing their knowledge to manipulate crowds to great benefit. Thomas Payne. Thomas Jefferson. Martin Luther King Jr.

If you instead mean regulation of what information enters a consensus... That's basically every history book. Every encyclopedia. The curated speaker list at a convention. The moderated comment stream on Hacker News.

And yes, such regulation can be used for ill also. The fascists in World War II used direct control of broadcast media to shape the thinking of the population. Of course, so did Roosevelt with his fireside chats.

I don't know what the future of information exchange in social media looks like. But I'm getting a strong sense that it doesn't look like Facebook and Twitter. I don't think those systems provide the right tools to build consensus.. instead, they seem to build cacophony. They reward enragement (because it drives engagement) and make it difficult for people unfamiliar with the topic to distinguish mainstream opinion from fringe.