This isn't a new situation. Free speech debates are as old as civilization itself. The printing press was at least as disruptive as the Internet, precisely because relatively small players could sabotage power of huge organizations such as the Church relatively cheaply.

I think that the old classical liberal principles still apply. A certain fringe of the population will eat any propaganda unthinkingly, domestic or foreign. But if a majority was so uncritical, democracies would have collapsed a long time ago.

We might actually be over the crest of max poisoning in social media. Lots of people have realized that such channels are not to be trusted. This is partly masked by the fact that a lot of new content is still churned out by dedicated players; silent majorities are silent.