The problem is obviously that the government shouldn't be regulating private speech. They pass these rules by saying "look how big Facebook is, they need to be regulated" when the actual problem is that they need to be decentralized. But then the rules don't apply only to Facebook, and worse, are designed under the assumption of a centralized service so that they entrench the thing that should be eliminated.

But there is nothing obvious about this? For one, this is speech that can only be done using otherwise regulated means. You couldn't claim "free speech" and build a radio tower that transmits long distances, as an easy example. For that matter, you can't claim free speech to allow concerts at your house. You similarly could not claim free speech to rent or loan out rooms of your house for storage.

As has been pointed out elsewhere, if you want to take the effort to connect and verify the different parties that are going to communicate with your server, you are almost certainly going to remain free to do so.

Do I think there are probably some concerning ways those burdens can be placed on folks? Certainly. But we already require inspections and other similar activities for things that individuals can do at home without an inspection. See the food industry.