> if John submits his post, then hires an army of bots to re…X it (?), he’s now published false information, which appear to have the veracity of truth.

By your hypothesis, he already submitted false information even without the bots. The bots are just an amplifier. But even with the bots, it's still a random person on the Internet making a claim.

> the scientist who replies with true, clear info will both get buried by the bots, and will have a less compelling message (because it is inherently more complicated).

The scientist won't get buried by the bots unless all the sites on which the bots are posting take no measures to filter out bot-generated content. Which of course is false: they do.

The message being "inherently more complicated" is a genuine issue, but it is not fixable by allowing some people to be "authorities" whose statements are taken as true with no critical evaluation whatsoever. The only real fix is for people to realize that, as the saying goes, all controversial questions have simple, easy to understand, wrong answers--and that to get to the right answer, you have to look beyond that.

In other words, the real root problem is how people form their beliefs. And the only way to fix that problem is to have people suffer bad consequences for having false beliefs. Again, having an "authority" whom everyone has to believe with no questions asked doesn't fix the problem. Historically, false beliefs have been more prevalent and have had more bad consequences under such regimes than under regimes where everyone can say what they want but nobody is taken at their word--everyone's statements are subjected to critical analysis.

> hundreds of people are refusing polio vaccinations (on this basis of it appearing to be a very popular position in what we’re now told is the online “town square”)

The problem here isn't people saying false things. The problem is the "online town square" which people are "told" gives them accurate information. The solution is for there to be no such place--for every source of information, from random posts on random web sites to the New York Times or the White House press room, to be treated as possibly making false statements and critically analyzed. (And of course even supposedly "authoritative" sources such as the New York times and the White House press room have been caught lying, many times, over decades. So it is perfectly reasonable not to take them at their word.)

Yes, it would be nice if we could actually have a genuine "town square" where only true statements could be made. But that is impossible, so we need to just recognize that and deal with it.

> the average person’s media literacy and susceptibility to propaganda

If this is true (I'm not sure it is), then the average person needs to take the bad consequences of their poor media literacy and susceptibility to propaganda.

As for the average person's effects on others, well, if you really believe that the average person can't, for example, be trusted to vaccinate themselves and contribute to herd immunity, your obvious response is to refuse to associate with the average person unless they take extreme precautions. Don't let the average person into your house without wearing an N95 mask. Don't socialize with the average person under circumstances where they might infect you. If that's what it takes for the average person to realize that their refusal to get vaccinated because of random bullshit on the Internet is stupid, then that's what it takes.

Having the government force the average person to get vaccinated without sufficient justification (which, I would argue, was the case for COVID--but not for polio, which was the example you used) just makes the problem worse, because now the average person thinks the government is out to get them instead of protecting them. Which is exactly what our new normal now seems to be, precisely because governments, and "authorities" like the mainstream media, have presumed to dictate to the average person what is true and what is right, and have been caught dictating wrong and obviously stupid things, so that now they have no credibility with the average person.