Ethics in design is an interesting one, and there’s so many variables that can come into play.
I heard of a team that was working on a project for DARPA where their job was to build an image tracking algorithm that could shine a turret mounted flashlight on a moving troop. That design brief seems fairly innocuous “oh, this would be good for helping to support people working at night in the field”.
The flip side of course is when it suddenly clicks that you replace the flashlight with a gun and you just built a highly accurate sentry turret.
That’s obviously more of an engineering challenge than a design challenge, but it brings up the question of where does that line come in to play. Designing for firearms isn’t an absolute - like Yo said there can be things that get designed for sporting purposes, things that get designed for safety purposes, or things that get designed just to make guns better at being guns. One way of looking at it is you are probably designing something that has the potential to save somebody’s life, and that’s fairly noble. The other way is you are enabling that’s going to go into a battlefield, and whether or not that makes you feel like you’re the guy pulling the trigger is another story.
I suspect the people who design nuclear missiles find a way to sleep at night though…