There are lots problem with this kind of terms:
- What kind of use is to considered military? Dual use goods? Software running on some computer in a military department that is used for "civil purposes" (think of some accounting software in the accounting department)? Projects that are also financed by some military pot of money (lots of civil research e.g. in the USA is financed by DARPA)? Consider that the precursor of the internet (ARPAnet) belongs to this category. Civil defense systems that are not owned/built by the military but by private security companies?
- If OSS people would tolerate such a restriction, the next people will come and also want to add restrictions to the usage of their software. At the beginning these will even serve noble purposes, but the time will come when people will use this kind of restructions to build their political agenda, such as
* must not be used for military purposes
* must not be used for animal experiments
* must not be used to produce hate speech
* must not be used for misogynistic purposes
* must not be used for homophobic purposes
* must only used by white people
* must not be used on Intel processors
* must only be used on RISC-V processors
* must only be used by citizens of democratic states
* only for noncommercial purposes
* only for research purposes
etc. So it is accepted practise in FOSS communities not to consider usage restrictions as acceptable.