Perhaps it's true that such projects aren't companies, but so what? It doesn't make them of any less value. In my opinion, producing something that people love and use is valuable whether it's done as a company or a side-project.
Is it true that such projects aren't companies? He lists "run it as a part-time business" as an option but isn't that already happening when "users can visit, use and even pay for" the project? Or is it not a company until a user pays and then it becomes ok to call yourself a founder?