I definitely enjoy learning other people's opinions on things I didn't realize I had an opinion on until I learned there was something to opine about.

To me the arbitrarily complex docker networking makes perfect sense. Especially in a compose setup. I want my containers to be able to talk to each other, but I don't want them on my local network or even accessible (sometimes) from the local machine. The various internal networks offer isolation of containers from the rest of the network stack. If I have a rails app in a docker compose configuration with PG, Redis, Elasticsearch, etc, in a development environment, most of the time I don't want the service/accessory containers anywhere near anything other than the app's container. And if I want several compose stacks to work together, I just put them on the same named network. I apologize if I misunderstood your point.

> The various internal networks offer isolation of containers from the rest of the network stack. If I have a rails app in a docker compose configuration with PG, Redis, Elasticsearch, etc, in a development environment, most of the time I don't want the service/accessory containers anywhere near anything other than the app's container.

Which can be achieved with normal routed networks with firewall on the “router” just fine, even on IPv4. Each container can have its own IP address, its own hostname and listen on a standard port, all reachable from containers and from the main OS of the workstation.