AI will get access to missiles, fighter jets, attack drones, and even nuclear launch codes - that's the fear.
Even when the bombs drop from the sky, at least those humans who had deleted their OpenAI account can rest easy, knowing that that they weren't the ones supporting the AI that will delete humanity.
Then the sane thing to do is to boycott that AI provider as well.
Opposing all AI companies tied to the war industry is a pretty vanilla principles stance, which also makes sense rationally if you want to "minimize harm".