There are other aspects of the origin story that seem to be myth. For instance, the idea that the Internet was designed to route around damage, and could also treat censorship as a form of damage, and therefore it was resistant to censorship.

I once spent a long weekend reading through the early RFCs. What I found was the obvious recognition of the fact that AT&T, which at the time had a monopoly on telephone services in the USA, was circuit-switched, whereas IP was being designed to be packet-switched, and clearly a packet-switched technology could be more decentralized than a circuit-switched technology. But that is the only shred of evidence I could find in favor of something like an ideology of decentralization. I could not find anything explicit in the design documents of the 1970s and 1980s.

As near as I can tell, the more grandiose claims of decentralization don't show up till the late 1990s, and those claims are not especially made by the technologists themselves (with the exception of Bob Metcalfe). It's mostly techno-utopians and libertarians who begin to make the bolder claims about how the Internet is fundamentally decentralized and resistant to censorship. People like Kevin Kelly, writing in Wired Magazine in the 1990s, made the most utopian claims about the decentralization of the Internet.

I've looked, and I've had trouble finding evidence of bold claims of decentralization, being made in the 1970s or 1980s, except in the very obvious case case that a packet-switched network is less necessarily centralized than a circuit-switched network. The myth gets built in the 1990s, and is then retro-imposed on the 1970s and 1980s.