In a free society, particularly the US where mistrust of the government and status quo narrative is baked into the culture, the ability to "sway public opinion"

In a free society, particularly the US where mistrust of the government and status quo narrative is baked into the culture, the ability to "sway public opinion" is a feature, not a bug. And on social media that ability is held primarily by the public. Not in the sense of social media being a public forum, but no true public forum does or arguably can exist on the internet anyway. Notwithstanding conspiracies about deepfakes and false flags and fears of "algorithms" and "Chinese mind control," social media is the only real balancing force against corporate and government propaganda that there is. Even with its faults I think it would be throwing the baby out with the bathwater to just have the government regulate it, which in essence would mean severely limiting the free speech rights of both the platforms and the people who use them. I know people think that government regulating social media means some kind of laissez-faire free for all where all legal speech will be allowed without consequence (which would be even less moderation than you find on 4chan) but that is very much not how it would go.