The “so what” is related to the fact that people aren’t telling others they have a permit from the pope, where the implied consequence is that the gullible person loses some money. They’re telling people that, for example, immigrants are the cause of all their problems, and that climate change isn’t real. The result of that isn’t that the gullible people are inconvenienced. The result is that they vote, en masse, for people who are actively hurting nor only them, but also the non-gullible people who are part of the same city/society/country/world. They do this based on information that is often provably false, but that the gullible people still believe, especially when it comes from someone in a position of power.
And that valuable service you mention, where gullible people become less gullible, never materializes if all the gullible people ever see is their own echo chamber, which continues to be disconnected from reality. The person with the pope permit to mine black holes has convinced enough people that he's definitely legit, and now he's digging a mine beneath your neighborhood, which will one day cause it to collapse, because there's gold in there and he can get rich selling it on the side. If you're willing to live with that in order to maybe, eventually, teach the people who bought into his permit a lesson, well, that's your call.
The type of gullible person that accepts these false beliefs about issues such as climate change and immigration isn't going to change their mind simply because Facebook starts censoring such content. Many people held such views before the rise of Facebook and other social media empires. Such views have been transmitted over old school media such as conservative talk radio shows for decades before the popularization of the internet.
All that is happening is a change in medium used to propagate such views. These people in question are only engaging with such social media channels because they find views that support their beliefs. Should such views be censored, they'll simply seek out other mediums.
I think the core problem is that many of these issues have been too highly politicized and now people can only engage with such issues on an emotional level. They only ask whether a view supports "their side" on the issue and care little for the actual facts.
Note, I don't even believe this behavior is limited to any side of the political arena. I've seen friends ostracized for simply considering positions such as the leftist argument for strict immigration standards to ensure a country has ample resources to care for their existing citizens and only takes additional members that will be a net positive contribution to societies available resources.
All in all, I think it is beyond the ability of social media empires to help gullible people become less gullible. All they can do is decide what content for gullible audiences they will allow on their platform. The more they restrict content, the more their user base will shrink as people seek out alternative mediums to find the content that supports their existing beliefs.
Well your argument proves it's about control. You justify your control by saying the opposing viewpoint is too dangerous.
Just realize you are not really changing minds nor preventing ideas from propagating. Ideas will propagate, people will believe ideas because of their mindset and upbringing, not because they read it once in some forum. The only thing censorship accomplishes is the Streisand effect.
And that valuable service you mention, where gullible people become less gullible, never materializes if all the gullible people ever see is their own echo chamber, which continues to be disconnected from reality. The person with the pope permit to mine black holes has convinced enough people that he's definitely legit, and now he's digging a mine beneath your neighborhood, which will one day cause it to collapse, because there's gold in there and he can get rich selling it on the side. If you're willing to live with that in order to maybe, eventually, teach the people who bought into his permit a lesson, well, that's your call.