> There also seems to be this idea that ISIS and white supremacists and whoever can magically infect others with their dogma as a form of mind control or something.
At scale, this is exactly the case. If the probability of the average person becoming radicalized is greater than the probability of the average radical de-radicalizing, then open discourse will, on average, increase the number of radicals until those probabilities equalize.
So now I ask you: how successful have you seen discourse at deradicalizing Jihadis, white nationalists, westboro baptist church members, anti-vax parents, or flat-earthers? Is it more, or less, successful than those groups at radicalizing new people?
>I want a society where people can say what they think and not get censored for it for the most part. It requires that we all come to terms with the fact that some people hold different opinions that we really hate.
Someone says "I want to diddle your kid". You tell them to never speak to you again. They say it to someone else. That person blocks them too. The same person keeps telling everyone that they're interested in child molestation. Free association says that we should all be able to shun that person because yikes.
But you say something different. That we shouldn't shun the potential kid-diddler. We should continue embracing them and their views, because shunning them censors them. And all views should be cherished and protected.
Or maybe you aren't saying that, but then its very tricky, because if everyone blocks them on facebook, they've been deplatformed. So why is that okay if facebook banning the person isn't? Or maybe it's that proclaim support for child molestation isn't okay, but proclaiming support for genocide is. In which case we're right back where we are now, just that your definition of "for the most part" is "expression of child molestation is bad, but white supremacy is fine". This brings me to my final point:
>I don't agree with what you say but I will defend to the death your right to say it
This only works when what you're saying isn't a threat to me. See how willing people 30-40 years ago were to defend to the death the right of black power groups to call for black empowerment. (hint: people got so scared the republicans banned guns)
If I start saying "we should kill all free-speech absolutists", how long are you going to defend my ability to say that? Only as long as I don't have power. Once I have the ability to actually carry out my threats, say, if I'm the president, do you really want me saying I'm going to kill some subset of society? Are you going to defend my right to say that? What if you think I might actually carry out what I'm claiming?
As long as the speech isn't a threat, people are okay with defending it. This is why no one really cares about flat-earthers, they aren't killing anyone, they're just the easy butt of jokes. Same with, until very recently, anti-vaxxers. Jenny McCarthy is kooky and their stuff is nonsense, but what's the worry? Well, measles, the loss of herd immunity, etc -> hmm, maybe we should stop this kind of thing.
Sometimes its possible to make the fix reactively. Kicking unvaccinated children out of school stops much of the harm that unvaccinated children cause, and in many cases forces parents to vaccinate their kids despite their views.
Unfortunately for explicitly violent groups, there isn't an easy reactive solution. You can't un-shoot someone.
As soon as people are threatened, they stop. "Expression of white supremacy is acceptable, but child molestation isn't" is just an expression of what you find threatening. What you're seeing is actually a shift toward more people speaking. Those who were voiceless before are speaking out and saying hey, this was really shitty before, let's not go back, and all the people saying otherwise are actually, truly threatening to me, so perhaps lets have them not say these things.
And on the other side you're seeing people threatened by this change in how people are considering speech, and feeling threatened, and saying "hey actually let's legislate these platforms so that I can keep spewing my garbage". White supremacists feel threatened by censorship, black people don't. That should tell you all you need.