This is a conversation that needs to be happening, and not just around whether you are okay with the government using your work to kill people.
Are you also okay with giant corporations that have enough money to develop their own tools use your volunteer labor to profit wildly and harm the public? (Also, private companies make tools to kill people as well. Just look at Palmer Luckey's Anduril, which produces military-grade drones and such. Or hell, any company that makes Tasers.)
Because the story of Free Open Source Software is also the story of the biggest accidental transfer of wealth from the working class to the capital class in world history.
Amazon Web Services wouldn't exist without Linux. Sure, they run their own flavor of Linux, but they've put in a bunch of their own proprietary bullshit and AWS is a fucking juggernaut. A big reason they're able to do this is because they use off-the-shelf Linux as a starting base and work from there. It cuts out a massive amount of labor to just lean on the labor of volunteers.
Now, not all companies are like this, I'll admit. Valve pays people to improve Steam in Linux and has wildly benefited the WINe team.
However, the vast majority of private companies lean on the labor of FOSS volunteers to make money without investing the same labor themselves.
It's honestly kind of a fucking travesty.
EDIT: Also, it's a bit ironic that RMS always claimed that his plans with GNU/Linux was to free people from proprietary gardens, yet FOSS has actually been one of the biggest creators of such gardens. I always had a soft spot for RMS, but he's wrong as much as he is right.