"As the Americans learned so painfully in Earth's final century, free flow of information is the only safeguard against tyranny...Beware of he who would deny you access to information, for in his heart he dreams himself your master. Commissioner Pravin Lal, 'U.N. Declaration of Rights' "
This had until recently been only tested for top-down information. Nowadays, everyone can be a broadcaster and we're seeing quite different results.
Doesn’t mean a locked down system is better though. With that they don’t have to bother.
What you need is a decentralized system resistant to propaganda techniques.
Rather what you need is a means for propaganda to be rapidly identified and refuted with counterarguments in a way that its would-be victims can see it.
We already have largely decentralized speech in the US via the internet. And much like how the printing press gave everyone a voice or how radio created Hitler, the internet is the modern age vehicle of populist messaging.
The reason someone like Trump can rise to power and consolidate said power is because he speaks simple and lies work in a decentralized system. Populist messaging is built on the fact that humans are naturally drawn to simple solutions and emotional responses. 90% of the time throughout American and European history, if you just tell people "this is ethnic/racial group X's fault!", that works.
Meanwhile the centralized platforms then have the incentive to maximize engagement and the power to structure things that way. And that's how you get Trump, because polarization drives engagement.
Only if you ignore everything about what got Hitler elected.
"Populists" winning is ALWAYS a result of the status quo being unacceptable to the general population. If the establishment is unwilling to fix that then they deserve to be removed from government. Free flow of information isn't responsible for that.