Those are all computer networks. It just happens that some of them involve computers running financial software, or computers running electrical control software, or computers running social software. Or computers running phone software, or light-bulb software, or toaster software.
Perhaps we don't need networked toasters, but I don't want to go back to a world where financial transactions are conducted based on hand-scratched notes and shouting on trading floors.
Computers are just too powerful to ignore. The problem is not that they are computers, but that some are locked down for user control of networking, but simultaneously designed insecurely as, say, "smart web cams" without the necessary incentives to keep them secure.