Possibly that’s true, but that is a naïve oversimplification. Do farmers feed murders? Everyone’s gotta eat, and it’s a job. It doesn’t mean they necessarily approve of each specific action to follow. One can’t even say the same thing for a fighter pilot. When you’re in a war zone, people shoot at you, and you might have to shoot back if you want to live. Do you think every Russian soldier is in support of Russia’s actions?

If you pay taxes, does that mean you’re a murderer? The taxpayer should reasonably know that their government might take actions that kill people.

Ethical concerns are serious, but layman’s use of the term murderer is pretty loaded. I think it’s far more appropriate to say that he worked for a weapons manufacturer, but context matters. Is this an ethical job? I don’t think that question has a simple and universal answer unless perhaps if you’re a pacifist and believe there’s no such thing as a justifiable killing.