Contributors to open source projects aren’t asking the question “should the thing be done,” they are asking the question “should
I do the thing.” I think lots of people fall into the general bucket of “sure, the military is necessary for a country, but I don’t personally want to work on it.”
It is a weird sort of diffused understanding of responsibility (we all pay taxes and our representatives vote on whether or not we’ll do war, after all), but I think it is not that uncommon. Lots of people don’t seem to want to be unusually personally responsible for military applications, compared to their peers, I guess?