1. Get exposed to $radical_group on social media
2. Go searching for $radical_group because their ideas are intriguing/edgy/whatever
3. Find the actual site of $radical_group, and now they control the entire process.
Think of it this way: you see a poster for some cool band that says "RadicalPandas's music will change your life. We have concerts, but they're secret and we can't tell you where they are because the man wants to keep us down". If anything, that sounds even more edgy and intriguing. So instead you just have to tear all of the posters down.
The actual planning and such happens on private sites with secret forums.
As a real-world example, a Danish right-wing nationalist network called ORG was exposed in 2011, after having allegedly been active since the mid-80s. Its members counted a number of well-to-do individuals, as well as members of the police and known violent white nationalists. The group ran and had control over several sports clubs, including martial arts and gun clubs, which they used for training members in street fighting and tactics.
They ran a database of basically every politician and public figure who ever espoused left-wing views, and thousands of ostensibly left-wing citizens as well, labeling them as "traitors" to be "dealt with".
At least one of their members was from the armed forces in some security-related capacity, and they had reasonably good opsec procedures in place.
I have no doubt that even after being exposed and having its members publicly named, the group or a new equivalent still exists, with new secret sites and a heightened level of paranoia towards possible infiltrators.
By deplatforming these people and driving them further underground and paranoid, we limit their ability to attract people through social media, for fear of exposure.
And somewhat related, does this mean you have as dismal a view of humanity as it seems, that you don't want people exposed to dangerous ideas? This all seems necessarily paternalistic. EDIT I can't imagine, for instance, trusting in democracy with such a view.
In fact, we humans already form a decent system for weeding out bad ideas/opinions, we just don't listen to our own past experiences on the matter. We found out that fascism is putrid and yet now we try to come up with a new system that will weed it out instead of just chucking it into the garbage bin and moving on.
It's not paternalistic or a dismal view of humanity or that "humanity cannot be trusted with such a dangerous idea", it's because the people advocating for it constantly lie about it and intentionally trick/indoctrinate others into following. Under the right circumstances of me growing up, I fully believe someone could have deceived me into believing it, so I don't think I'm better than anybody who got sucked in. We can trust in democracy as long as we take proper precaution against things that prey on the freedom of expression and association in order to remove those rights from others.
Put another way, what real benefit is there to "freedom of speech, except for advocating fascism" as opposed to "freedom of speech, no exceptions"? The US already doesn't have pure unrestricted free speech because there are exceptions made for outlier situations where free speech is not protected in efforts to secure the safety of others. That hasn't led to total collapse or censorship.
Personally, I feel there should be legal protections for all speech, but not protections from social ramifications. By this logic, I am totally fine with the idea of punching fascists. Which itself could be hit with assault charges, but then, how many juries would disagree with the reasoning for the violence? Let the masses decide for themselves, basically. It's what bothered me about the firing of James Gunn and Roseanne both despite their polar opposite politics. The companies that employed them cared so much about what the public thinks or feels that they couldn't be bothered to let the public decide for themselves to support either celeb or not. (And I know Gunn has since been rehired, but this happens so often, my point stands.)
I lean towards anarcho-communism myself, generally close to the original communist definition of libertarianism. So my answer to which authority should run things is "none". Facebook runs their own ship and are free to choose which content they will platform. While I would prefer a complete absence of hierarchy in all aspects of life, I think we can agree that this is probably not going to happen at FB.
I also strongly support anarchistic deplatforming and generally hindering fascists, nazis, racists and other bigots from spreading their noxious views. We have to realize at some point that some views simply aren't worth spreading.
Do you have any evidence to support that statement? Would you expand on why you think so? I would estimate that by driving them more underground, you make them seem more cool in the eyes of angry teenagers. You also make them more radical because underground their opinions are not exposed to contradicting views. In my opinion, we should do exactly the opposite - we should give them platform to speak and oppose them. Isn't that what open society is about?
There are a few studies in this thread that conclude similar.
The whole sunlight is the best disinfectant trope is only a trope, not a truth.
See also any conspiracy theory and the amtivax movement. When groups appeal to fear, not logic, as a recruiting tool, you can't logic people away.