Earlier quoted context omitted.
Honestly I think military is just a scapegoat for these people, their real mission (like many before them) seems to be using the lack of CoC acceptance as their own weapon to justify bullying them for having opinions they don't like. That has always been the MO. They want the CoC to be able to silence undesired speech in the first place, and if they refuse, it becomes their strawman to allow them to keep arguing the…
While the phenomenon you describe certainly exists, it is vital to separate it from the phenomenon of not wanting to support the US "defense" sector. I do not identify as a leftist, and would not be considered one, but as an aerospace engineer I would never work for something that aids the US war machine. Those weapons are never used in "defense". Do they defend an unsustainable way of life ? Sure.
How is that not defence?