I was pondering the same thing and to me the answer is a contractor sold something to the DoD and Anthropic pulled the rug out from under that contractor and the DoD isn't happy about losing that.

My speculation is the "business records" domestic surveillance loophole Bush expanded (and that Palantir is build to service). That's usually how the government double-speaks its very real domestic surveillance programs. "It's technically not the government spying on you, it's private companies!" It's also why Hegseth can claim Anthropic is lying. It's not about direct government contracts. It's about contractors and the business records funnel.