This is not answering the question.. and HN ain't US only.
You can say the same for any other country... What if Japan employee refuse, but American want that anyway? What if China employee refuse, but Russia employee want that anyway?
The implication are still the same -- social, culture, jurisdiction, national interest, company interest don't share the same boundary and don't align on their priorities.
I don’t think they’re refusing all military involvement. Autonomous-decision making is the problematic part.