[tannhaeuser]

I think the reasoning behind RDF using URIs/IRIs for nodes and predicates is that this gives a globally unique naming hierarchy (backed by DNS in turn), such that when combining heterogenous data there's no name clash, and at the same time allows for liberal use in closed DBs via "urn:" URLs. But yeah, if the linked article insinuates that dereferencing RDF URLs is useful or even common, that would be false IMO.