There are to ends of the information transation, and both ends usually have a "provider" of some sort. Certainly the consumer of info has a provider.
I took your remark that the purveyor of content has to be hosted, as all websites are. I was pointing out that the usenet newsgroup model does not have a purveying end provider the same way that websites do.
You may recall the days of dialup BBS, which included a couple of networking schemes - fidonet being one. Usenet newsgroups are a distributed purveypor.
Maillists is another means of connecting groupls a people interested in a particular topic. That uses the same port (poers) are e-mail, which your ISP could shut down too, but that would be objectionable to the customers.
email and usenet are on different ports.
shutting down the usenet port would have no effect on email.
https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers