And it's not that hard to explain to people. Just like we have been educating the general public on how to eat more healthily with the food pyramid, we should do the same with online interaction. Stating opinions online is ok from time to time, but if all your interaction with the "real world" is not on the "real world", you are probably missing perspective, and you might get sick with conspiracionist thinking, extreme political polarization, biased narrative poisoning. Which we are seeing that, when reaching enough people, start to become contagious even outside the internet.
It's totally possible to interact more responsibly on the internet and social media too, but we kinda need to understand what these environments are lacking compared to the "real world" and work on more healthy practices.
If it is really so difficult to sort out the misinformation, then the next best thing would be to make the feed/site as boring as possible. Of course Facebook will never do this and another site would just take its place if it did. But I think it's important to realize that there are other strategies besides sorting out all of the misinformation (which may truly be a difficult/impossible task).
This doesn't seem to be in keeping with the spirit of discussion or rules on HN.