> Is it really so terrible to research arms for the people who risk their lives keep us safe?
If this was the only thing the weapons were used for, then maybe people wouldn't be upset about this kind of stuff.
The same arms will however also be used to extrajudicially assassinate people based on nothing else than their phone signal, in countries we are not at war with; they might be sold to regimes like Saudi Arabia that kills countless civilians in places like Yemen; they might be used to fight wars based on reasons the administration knows to be false; they might be used to gun down civilians by private contractors; the list goes on.
I'd not be opposed to participating in military research if the weapons were actually used "responsibly" (I know that's a somewhat subjective terms, but most of my examples are quite clearly considered immoral by most people).