As a US citizen in a place that's more or less evenly red/blue split, and given the trajectory of US politics lately, I'm worried that if I help improve US military technology, it will later be used against me or my neighbors.

Even if the current posture for whatever nation is predominately that of defense, you have no idea what is going to happen in the next few years geopolitically, or even just when your country has new leadership. The defensive capabilities you help build today could easily be used for offense tomorrow.

I wonder, of the many hundreds of billions of dollars the US spends on defense every year, how much goes to those military operations to which you linked.