Also, I haven’t yet heard of any developed nation that has figured out how to maintain its national sovereignty with no military protection at all (either through its own forces or as a protectorate of a larger nation).
So if we accept the idea that having some kind of military force—even a purely defensive one—is likely necessary, then it follows that we should support people of conscience who choose to take on that role. That doesn’t mean that we should venerate soldiers who do bad things, just as we shouldn’t venerate teachers who mistreat students. But suggesting everyone who enlists is guilty of war crimes by association is just absurdist, classist nonsense.