While official Docker image would sure be nice it would also take away resources from other dev tasks.
Community can easily offer base images for DayZ and also Dockerfiles for complete images even if binaries could not be redistributed with prebuilt community images.
After all, first time I built my own Docker image for DayZ it took me just about three hours to get working image up and about one hour to get server up with few mods. This was my first time ever setting up and launching DayZ server or steamcmd (but not first time with docker, containers or linux).
I do believe in the end it would be better if BI sticks with game dev focusing resources there and community provides server tools, base images for containers, setup scripts, container documentation and such.