A website typically run on a dedicated server, not mirrored elsewhere, under the complete control of it's owner, and hosting. So while no one really "own" usenet different subjects own, can censor, destroy etc a website and their reader can't really do much about that.
We have of course other types of site, ZeroNet is a nice example, but they suffer many problem, they are far less available and known compared to usenet and their "ownership" is still partially in singe subject hands.
A simple practical example: what happen to your HN post if HN disappear? How can you or us "posters" united can do in that case? Vs what happen if a newsserver disappear?
Individual websites: the sole owner of the domain name determines all servers that can serve content, thus all behavior, which is pretty conclusively non-federated.