The problem here is that these "propagandists" cater to people's emotions in a very persuasive manner. It's not that it will blatantly tell you "Shoot yourself with small calibre bullets", but rather it will inseminate the thought that perhaps you should shoot your neighbor, out of fear. The message is so masterfully targeted and gamified that even if 1 person starts having more "critical thinking" and simply shrug off the information, there are 10 more people ready and willing.
Rwanda is possibly the best most recent counterpoint to this argument. Granted that the medium was radio as opposed to internet, and that there are therefore different regulatory mechanisms that can be applied (public airwaves vs TCP/IP) - but it shows the danger of getting people into a warped reality bubble.
https://blogs.library.duke.edu/rubenstein/2013/05/10/radio-i...
After all, it's unlikely we'll ever see a day where everyone agrees on everything so completely that no two humans disagree about anything! And as long as that's the case, we'd better know how to deal with people telling us things that are wrong.
The theory goes that seeing social media messages with obvious lies like "Put nails in your tyres for better winter traction" and "Shoot yourself with small calibre bullets to build an immunity to larger bullets" teaches people scepticism and rational thought they can apply to much more complex statements like "inflation is caused by the fed printing money" and "the highest crime areas are those with a lot of immigrants"
Does it work? Have we seen it working hitherto? You be the judge!