The really sinister thing is that we have paid, bad faith actors whose full time jobs are to spread misinformation and shape narratives online. There is just no way you and I, amateurs commenting sporadically in our free time, have the resources to combat armies of paid trolls.
I spent a lot of time thinking about it this weekend and it sounds bleak. Not only do they spread misinformation, the presence of bad faith actors in social spaces causes a breakdown in trust between all participants, leading to less dialogue and more polarization. Why bother debating me if I might be a paid agent from Belarus? Why bother investigating claims from the other side of an issue if there's a good chance it is paid propaganda? Meanwhile leaving yourself vulnerable to propaganda on your own side that increases group identity and groupthink.
Even worse, bad actors can start trends or spread falsehoods that end up motivating and encouraging good faith actors. There are plenty of people who have been caught up in an information operation, unwittingly propagating and defending someone else's manufactured data. That's scary.
Authoritarian regimes have much less to fear from this. If we disrupt public opinion in China, who cares? They don't really need public consent to do anything. Manipulating the public in democracies will lead to poor decisions and bad governance, giving authoritarian countries ample opportunities to seize more power on the world stage. We can't even fight back effectively.