Containers are not programs. And even they were, they absolutely do not adhere to the Unix philosophy.
> Kubernetes is the operating system in this analogy
I've heard this enough times and seen enough K8s systems in production that I'm labeling this "fluff". K8s is an operating system in the same way that "everything is everything". K8s is software that manages containers and their resources. I think of it more like a virtual environment than an operating system.
From Wikipedia:
> An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
You can generalize "software resources" as container resource limits. You can generalize "common services" as the network and filesystem layers. And you can generalize "computer hardware" as kernel configuration on the control plane.
All of these are purpose built abstractions built on top of the real operating systems. By that logic you could call any virtual environment or virtual machine an operating system. And if that's the true then the comparison isn't useful at all.