Social media is central to many people's lives. It is increasingly a focal place for political expression, too, with many having no means of doing so other than social media. However, there are reasons to think humanity is better off without it.
Stop (most) fake news
It is likely true that lies spread faster than truth on social media. Social media users are able to lean on one another as sources of information rather than going to official sources that at least have some (albeit not always) reputation to maintain for accuracy. Random people you meet on the internet are under no pressure to be accurate or reliable. In addition, mainstream news sources are able to get away with more fakes with the help of social media, since it allows to creation of media that can be quickly deleted and swept under the rug when it is not convenient, or followed up with haphazard apologies.
Improve mental health
There is adequate reason to think getting rid of social media would decrease mental illness and especially suicide among young people. Such a move would be a problem for some though, and result in them being more isolated. However, those isolated people would just be fringe minority communities who naturally are isolated anyway. If the majority at risk, their welfare has to always be addressed before that of any minority.
Reduce political interference
Dismantling social networks would remove a threat to governments by unpredictable and profit-driven actors. It would remove the ability for foreign governments where the social media companies are located, mainly the United States, to interfere in the internal affairs of other countries. Likewise, it would allay Western fears of election interference by Russia and China, which are continuously voiced by politicians and journalists.
Improve political discourse
Social media may be ruining political discourse simply due to the way it works. Whether you are a conspiracy theorist or someone who just relies on mainstream media, you are similarly being duped by an industry that focuses on the endless, mindless consumption of news under a model intended for entertainment, rather than stopping to analyse or understand the world.
Of course, it is highly unlikely that social media will be eliminated for the reasons above, because it is too lucrative to the companies involved and the politicians they influence. Nevertheless, governments should certainly create options to get rid of it in the least disruptive way, in the interests of preparation against foreign interference. How to effectively do this will eventually be the subject of another post.