You are so close to breaking through..
> Otherwise, if democracy is good and votes should matter and at the same time voters are a mob subject to manipulation... democracy is what? A system of government by whoever can do better propaganda? Why would that be good for anyone except those who do propaganda?
Yes. And you are already waking up to that in your next question.
> One question I would ask if people are just a mob, who is actually pushing the buttons? Owners of media, political leaders, are also humans, no? They have the same weaknesses, at least in principle.
> If you accept some people are different (those who command and control propaganda) then we must conclude that not all people are vulnerable to it
Why would those who do propaganda not be susceptible to disinformation, or the Dunning-Kruger or Gell-mann Amnesia effects? Every person is susceptible to disinformation. The difference is that those in power can disseminate disinformation at scale.
> so maybe it's a spectrum. But still democracy sounds like a bad idea, as a majority are probably on the low end of the spectrum, and the majority rules.
Hence "tyranny of democracy". Many places in the First world are now experiencing this, where 'green' programs and and social progress are being dismantled en masse because of a slight majority. Worst of it is, long term these decisions will carry a massive financial burden. The LA fires with $250 billion+ in damages are a herald of that.