Having worked exactly in this space, this is a perfectly normal document. Architects and principal engineers aren't bothered to the point of distraction but it is definitely something that's taken seriously. And it isn't just the DoD, it's every federal agency.

You may also find the US Government Accountability Office interesting.

They do a mix of various reviews and audits of government services and projects, and publish and targeted recommendations; But to form a basis for those reviews and audits they have a position on what "good" looks like and publish that as guidance.

[1] https://www.gao.gov/

I used to work in a really niche engineering field. The amount of stuff I used from documents released by the US military was non-trivial. Never anything directly, but most of the time the docs were useful enough to shed deeper light and context on the trade publications and standards I was using when the history and intent behind a lot of calculations wasn't clear.

The Space Force is cool, but honestly, we desperately need a Cyber Force.

It means the defense department or its vendors are using Kubernetes, which they are. That should keep them up at night.