The issue isn't software developers working with the military. It is a matter of offensive U.S. military operations and the associated self-serving geopolitics being treated as countercultural.
Actually, The Campaign to Stop Killer Robots fired its campaign manager Ousman Noor as a result of him advocating against the IDF's killings in Gaza. The Campaign initially denied that it was over his Gaza advocacy, but eventually admitted that it was because of him speaking to diplomats which he met through the Campaign. Many members of the campaign support the IDF's arguable genocide, despite how surprising that might be.