The USG should not be in the position that it can't manage key technologies it purchases. If Anthropic doesn't want to relinquish control of a tech it's selling, the Pentagon should go with another vendor.
You are misrepresenting the situation. The debate isn't about whether they should go with another vendor or not. Everybody can agree that they would have the right to pick a different vendor. That's not what they're doing, they're instead trying to force Anthropic into doing what they want by applying a designation previously only reserved for Chinese companies like Huawei as punishment for taking their stance, with an unspoken agreement that if Anthropic backs down and allows full usage then the designation will be removed
Anthropic isn't preventing them from managing their key technologies. If my software license says 1000 users, and I build into the software that you can only connect with 1000 users, is your argument that the government can no longer manager their tech?
That my software should allow license violations if the government thinks it is necessary?