Let’s put it this way, The DoD is buying pencils from a company. Should that company be prohibited from using Claude?

You are confusing the need to avoid Anthropic as a component of something the DoD is buying, with prohibitions against any use.

The DoD can already sensibly require providers of systems to not incorporate certain companies components. Or restrict them to only using components from a list of vetted suppliers.

Without prohibiting entire companies from uses unrelated to what the DoD purchases. Or not a component in something they buy.