Really it’s internal threat security vs external threat security.
Measures to reduce personal security also reduce the security of the traditional armed forces.
1) The armed forces use most of the same networking software and hardware as civilians. They also rely on the same protocols.
2) In a total war scenario, like Ukraine, civilian communication infrastructure becomes military communication infrastructure. See soldiers relying on phones for communication and apps to aim artillery.
3) The vulnerabilities that get built into civilian communications are obvious cyber warfare targets.
The framing of privacy vs security tricks the traditional armed forces into thinking that they have the same interests as the NSA.