Probably because in many cases the assumption is that the dev and main editor are the same person? It's not a great assumption anymore (since many WordPress in

Probably because in many cases the assumption is that the dev and main editor are the same person? It's not a great assumption anymore (since many WordPress installs are now set up by agencies and dev teams for non technical clients), but it's likely a holdover from the days when most people installing it were also the main designer, developer, content writer, etc (read, bloggers).