Anthropic doesn't object to fully autonomous AI use by the military in principle. What they're saying is that their current models are not fit for that purpose.
That's not the same thing as delivering a weapon that has a certain capability but then put policy restrictions on its use, which is what your comparison suggests.
The key question here is who gets to decide whether or not a particular version of a model is safe enough for use in fully autonomous weapons. Anthropic wants a veto on this and the government doesn't want to grant them that veto.
Let me put it this way–if Boeing is developing a new missile, and they say to the Pentagon–"this missile can't be used yet, it isn't safe"–and the Pentagon replies "we don't care, we'll bear that risk, send us the prototype, we want to use it right now"–how does Boeing respond?
I expect they'll ask the Pentagon to sign a liability disclaimer and then send it anyway.
Whereas, Anthropic is saying they'll refuse to let the Pentagon use their technology in ways they consider unsafe, even if Pentagon indemnifies Anthropic for the consequences. That's very different from how Boeing would behave.