We're talking about the US here. We haven't declared war since 1953. None of the fighting we've done has been to directly defend citizens of the US, other than arguably going into Afghanistan and trying to root out Al Qaeda and Bin Laden.
No, US companies supporting the war effort by increasing US soldiers' survivability are only ENCOURAGING the US to fight more wars. Imagine how much killing the US would do if US soldiers were 100% protected from harm? The only thing that stopped Vietnam, and caused draw downs in Iraq and Afghanistan was the public being unhappy with how many soldiers were dying there. Its an unfortunate reality that dead servicemen are the one thing that prevent politicians from sending US troops to even more places.
Whether you agree with this or not, this is why a lot of tech workers don't want their work to be used to support the US war effort in far flung places with a highly tenuous attachment to the safety of US citizens. If the whole population of the US ever gets behind a war again, which hasn't happened since 1941, the world better look out.