The article doesn't mention IPNS at all, nor does it talk about the need for mutating an image while it is being shared, so I'm not sure why you think IPNS is even desirable in this use-case?
https://docs.ipfs.io/guides/concepts/ipns/
TLDR IPNS are pointers to IPFS content (ie "latest"). If you're tracking your containers and pinning to their versions elsewhere, might not need IPNS.