Using Kubernetes doesn't imply using Docker, even. K8s is 99% an orchestration system, like Terraform or CloudFormation. One resource among many that it orchestrates is containers. It can also orchestrate regular VMs.
That being said, I also disagree that Docker isn't suited to running a DBMS, assuming you actually have a large enterprise (or cloud) datacenter backing your Docker daemon. In such cases:
• You'll probably have a large enough pool of Docker machines (k8s or not) that you're going to be deploying your DBMS container in a way that reserves an entire instance just for it (or it + its accessory containers);
• You'll probably have a SAN, and you'll have many enterprise-y reasons (e.g. live VM migration) to prefer backing your DBMS with said SAN, rather than with local instance storage.
If both of those are true, then Docker has no disadvantages compared to deploying your DBMS as a raw VM.
As an "enterprisey" person, I disagree. I've seen a lot of enterprise infrastructure that looks like toddlers built it out of lincoln logs. And I've seen SANs lose connectivity much more often than a pool of independent local disks all going bad at once. On top of that, databases run on VMs that aren't on hypervisors dedicated for running databases results in shitty adminning and overcrowded VM pools destroying database performance+reliability.
Cloud-ish infrastructure is often good for running distributed decentralized databases, but try running Oracle in a bunch of Docker containers on a crappy OpenStack cluster and soon you'll be crying into your scotch.
These efforts to make people think it's a good idea to run databases on K8s are misleading people, and god help those poor teams that waste years trying to stabilize something that a fancy web page and a youtube tutorial said was a great idea.
That being said, I also disagree that Docker isn't suited to running a DBMS, assuming you actually have a large enterprise (or cloud) datacenter backing your Docker daemon. In such cases:
• You'll probably have a large enough pool of Docker machines (k8s or not) that you're going to be deploying your DBMS container in a way that reserves an entire instance just for it (or it + its accessory containers);
• You'll probably have a SAN, and you'll have many enterprise-y reasons (e.g. live VM migration) to prefer backing your DBMS with said SAN, rather than with local instance storage.
If both of those are true, then Docker has no disadvantages compared to deploying your DBMS as a raw VM.