Given the ambiguity of the phrase "military use" when the military does, in-fact, use it for things the military does - I am not confident in the slightest with Arduino's use of language here.

Indeed. Also because any big organisation or corporation can both do evil and good. Often research projects with guarantees to release knowledge or some other improvements such as to software projects under a permissive licence.

How would you want to see this further clarified?

> Military Use: Use by or for any military organization or for any military purpose, including but not limited to projects sponsored or paid for by military organizations, or use by the U.S. Department of Defense (except for DARPA), U.S. Armed Forces, U.S. Department of Homeland Security, U.S. intelligence agencies, or any foreign counterparts of the foregoing.