People have been making this claim because the Secretary of Defense personally issued a statement demanding that "no contractor, supplier, or partner that does business with the United States military may conduct any commercial activity with Anthropic". We're not going to play this absurd game where government officials issue fascist instructions and we all pretend they said something more reasonable instead.
Except you and many others are accepting what he said as if it were true, that statement is false. And hiddencost and others are just parroting it instead of describing the real situation.
This designation means Athropic's systems can't be used in DOD work, but many companies that work with the DOD also do work outside that. That separate work is not restricted with respect to the use of Anthropic's systems. Repeating a lie as if it were true is just dumb, it helps spread that lie.