> And all those companies can choose not to work with them too.

Right, and if they chose independently to do so it would be their right. What makes this problematic is that "all those companies" did not choose to not to work with the Pentagon (or with Anthropic spefically, for that matter). They were compelled to using using a regulatory tool which was originally intended to combat hostile foreign espionage.

That's not a "choice" made by those third party suppliers. The Pentagon is using the Supply Chain Risk designation as a contract negotiating tactic.