While I appreciate your sentiment, and would describe myself as a pacifist as well, I am unable to say that self-defense is unethical. However, even in 10th grade, when we first entered Afghanistan, I found the concept of the wars in Afghanistan and Iraq appalling, unjustifiable, expensive, unproductive, and without a way out. Nearly two decades later and that all seems to be true.
That said, I wouldn't find myself saying "don't retaliate" if there was an actual force striking the country.
Being unable to categorically rule out self defense, springing from/combined with, being unable to control others means that we may need to defend ourselves, and if we must, we should be capable.
I don't know if I could work for the military, directly or as a contractor, but I'm not ready to say that every member in uniform and every contractor is amoral for doing so.
Anyway, my point is even if you convinced your entire country to never take up offensive arms, would you be able to also convince everyone else to as well? Would you be willing to tell your countrymen not to take up defensive arms?