Isn't it a literal supply chain risk, though?

They want their products to not be used for some purposes. That's fine, that is their right. But that doesn't just stop at direct purchases. If the US buys from a defense contractor who bought from abthropic, that really isn't that different from buying direct. The moral hazard is still there and the risk that anthropic will try to prevent their product from being used in that fashion is still there.

I think anthropic wants their cake and to eat it too. You can't take a principled stand against something and then be shocked the thing you are taking a principled stand against might think you are a risk.