US government does not have a public fund or tax to pay for the development of a government sanctioned Unix/GNU operating system by a US company. Once that happens, then this issue goes away.
Well, it was. It's not the reliable, stable OS it was only a few years ago. It has really pushed the envelope for stupid since its first foray into Dumb for EL6.
A. Has laws that could have prevented IBM from buying RedHat.
B. Knows it relies on RedHat for securing critical systems.
C. Didn't do shit about the purchase.
Ideally, each government would look out for the public's interest, in these things. But in this case, it failed to even look out for it's own interests (which would have aligned, in this case).
In reality it is more complex. However, I know the air force uses a ton of Linux and related tools such as Kubernetes and Samba. Who would've thought a fighter jet would be running kubernetes