Society has a right to defend itself. It does so via uniformed police officers who are authorized the use of deadly force.
Individual citizens also have a right to defend themselves via deadly force: in public from threats of death from another individual or individuals; and in their home in the case of criminal home invasion. Some individuals choose not to keep weapons of deadly force in their homes and rely instead upon the police. Often these people end up dead when either the police cannot be summonded, or the police do not respond in a timely manner.
The same is true of countries. Countries have a right to protect themselves from invasion, from terrorism, from war-like acts on the part of other countries. And each country has the right to raise an army from among the citizens which it has a responsibility to protect.
Personally, I feel that it is up to each individual to decide for him/her self as to whether s/he will be a part of the armed forces and make use of deadly force, or if they will accept non-combatant roles, or if they will refuse association with the army in any capacity. But the emphasis on the above, the key word, is individual. If the individual wants to reflect the demands of some outside agency, such as the Watchtower Bible & Tract Society, then s/he has every right to do so. However, if the individual concerned wishes to keep their own counsel in the matter, they have every right to do that as well.
It's all a matter of whether or not the individual wishes to serve the interests of the "superior authorities" as interpreted by a religious cult, or whether they will be guided by the spirit voice within themselves.
And we are bound, IMO, to continue in this pattern until each and every so-called "soverign" country on this planet recognizes that there is one and only one legitimate soverign force acting on this planet, and ALL countries follow the lead of that soverign force: the existential, infinite creator.
IMHO
francois