And the nature of DoD research back then was more generally applicable to things besides killing. The Mansfield Amendment is what turned ARPA into DARPA and pushed to curtail pure research. If you couldn't kill someone with it, it wouldn't get funded.
The Mansfield Amendment of 1973 expressly limited
appropriations for defense research (through ARPA/DARPA)
only to projects with direct military application.
Some[who?] contend that the amendment devastated American
science, since ARPA/DARPA was a major funding source for
basic science projects of the time; the National Science
Foundation never made up the difference as expected.
https://en.wikipedia.org/wiki/DARPA#Later_history