You may not need Twitter or Facebook, but you do need a registrar and a host.
What happens in your hypothetical when those private entities say they are not subject to the first amendment?
Who owns the internet? Serious question. But I believe registrars and hosts are most likely owned by corporations and they have constitutional rights.
“but you do need a registrar and a host.”
No you don’t.
Both can be bypassed. Apply directly to ICANN for your name and IP block.
Buy your own network access and build your own servers.
Private corporations do it all the time. It’s very, very common.
“You may not need Twitter or Facebook, but you do need a registrar and a host.
What happens in your hypothetical when those private entities say they are not subject to the first amendment?”
It may not be a first ammendment thing, but more of a public accommodation thing. For the answer to that, let’s refer to the recent private entities who declined to provide their services towards a cause they opposed. I’m speaking of the bakers, photographers, florists, property owners, etc., forced into servitude by supporters of militant homosexuals. I’m still trying to figure that one out. If you can be booted from a web hosting service, why can’t you be denied a cake?