> for someone to have never even heard of C# and to be working full time in a senior level programming job, you have to be completely and utterly isolated from any kind of programming community.

The majority of defense contractors I know don't spend time in the "programming community" in their off hours, both because it's contractually too cumbersome to do so, and because they're doing other things in their spare time. They may spend time in the "defense community". It's very different culturally from SV.

> just because I don't use node js, ruby, or perl in my work doesnt mean i have an excuse to not know that they even exist. how can you choose the best tool for a job if you only know C++ and Ada?

node.js, ruby, and perl are not acceptable for use on real-time systems nor safety-critical systems.

> how can you choose the best tool for a job if you only know C++ and Ada?

Having worked in that world for almost 10 years, I can tell you that this choice is not up to you. You are told what tools you will be using, typically driven by government customer "experts" and inter-company politics.