The risks are overblown, and so its ok to create places with decentralized freer speech.

Firstly- I removed the parts where you stated that this is like the phone network.

Phone calls are temporally limited, once you are done with a call its over. You can't hear that voice again, or relive that conversation, except through memory.

Text on a forum combines the worst of phone calls and books.

Not only is it easy to create and respond in real time (Like a phone, and unlike books or letters), but it is also persistent so people can read and participate in that moment of emotion repeatedly (like a phone call).

These are great and greatly bad depending on how they are used, but they are dramatically different from the way a phone call impacts human beings.

Which brings us to the second point - it isn't only the information, it is the emotion, or in combination the "content" of speech on forums/social media that matters.

Having actively tried to push for free speech and then managed speech, I can guarantee that without moderation, forums/social spaces collapse. They fall victim to our neurology, and the scale of people on it.

So you can't avoid the use of force here, the question is the amount of force being used, and whether it is commensurate to the specific event it is being used to mitigate.

The modern equivalent of the telephone network is the internet, specifically the cables, routers and switches that allow us to communicate.

The owners of said equipment are not liable if child pornography is send through their wires.

That is not a problem, we don’t close roads because child pornographers use them.

But the end point is a totally different matter.

But to the point: moderating the (tone of) the discussion, is essential for a good discussion. You can’t have the trolls interfering.

I think moderation and thus limiting free speech somewhat is actual fundamental essential for a good debate or discussion.