As shown in this discussion, a lot of the calls for internet regulation centre on regulation of speech. This is the wrong ground on which to be fighting the problem of propaganda.
In my view, the bigger problem is how feedback loops and other features of systems can be gamed. The central problem in a lot of social networks is one of power. These systems 'reward' certain posts or posters with greater distribution/prevalance/amplification, so it follows that some speech is given power over others. If the already powerful can game these systems (getting networks of bots to 'react' to posts to drive their 'engagement' scores); if the systems depend upon feedback loops that generate near-exponential concentration of that power (more followers create higher distribution, creating more followers, etc), then the systems - far from being neutral - are generating a real problem of asymmetric power. I'll explain why this matters.
In order to have democracy, you need a healthy public sphere.
In order to have a healthy public sphere, the classic liberal argument is that you need freedom of speech (within limits) to create a marketplace of ideas.
But our current marketplace of ideas (social networks) resemble Amazon's marketplace where 'promoted' equals paid. If you don't pay in cash, you pay in resources: you need to create engagement, or invest enormous energy in generating sales momentum in order to get featured. So the marketplace largely becomes the preserve of the already powerful. If you don't pay to play, you get buried. The enormous democratic promise of social networks (that we all have a voice) becomes almost irrelevant if we cannot make ourselves heard. The value of freedom of speech becomes almost irrelevant if some speech is privileged via powerful feedback loops, and other speech is buried. We can defend these systems on the grounds of liberation from the dread hand of the censor, but we need to recognise also that these systems, by surfacing the 'engaging' conspiracy theories and burying the vast majority of speech (the speech of those who have not paid to play), are de facto censors by other means.
The systems - algorithmic sorting, tracking of user behaviours, hyper-targeted advertising - are the problem.