As someone who knows people in warzones(not someone in them myself), and as someone who is left-leaning politically, I believe anything Nix-related should not accept contracts or sponsorships from companies whose main business is killing others. I find those kinds of companies to go against my personal beliefs, and I believe that many others(as indicated in this thread) hold that belief as well.
Also, many friends of mine(along with myself) who may attend these events otherwise may not feel comfortable with coming to events sponsored by such companies. In general, these companies don’t seem very good for humanity in general, and I feel that as an organization, the NixOS Foundation should be trying to position itself and the community at large as a community that cares about accepting others(of any gender, race, age, creed, etc) and cares about human rights for all. These companies are antithetical to that, and so I vehemently believe that it would be a bad decision to accept any defense contractor or other company that relies on killing as their primary business.