There are two gigantic issues with social media as we have it now.
Like it or not, we have monkey brains. They did not evolve to deal with the scale of information (and misinformation) that they are being exposed to. The monkey brain sees that something has 15,000 re-tweets, and assumes that one of those 15k other monkeys viewed it and vetted it.
The other is that people are getting a firehose of content into a single mental context.