Podman is exist since 2018 (and for RHEL only on that time), but docker since 2013 and it has had a wider adoption and knowable by the Community. Podman also was not available for Windows and WSL (even v1) was not exist, and WSL did not work with the containers until wsl2 anyway, but there was a Docker Desktop.
We did not want to scatter resources to support many different platforms and methods to run it in different container solutions and explain to each novice how to run a binary, so docker was a tradeoff, simple distribution and manage and also cross-platform.
Now Operators have much more wide choices how to run storagenode, or containers, include Podman, Rancher Desktop and many other alternatives like Kubernetes, Nomad or docker swarm.
Your pull request is very welcome: GitHub - storj/docs: Source for Storj docs