Is killing ever right at all?

From the book Think on these things, K says, Soldiers are told to kill for the sake of marvelous utopia in the future as if the man who tells knew all about the future. Do u think that killing is a right profession? Whether it is for your country or for some organized religion? Is killing ever right at all? For any idea that certian people great or petty, have said is right.

My question to K is, Soldiers are not trained to kill for future utopia. They kill because, if they don't, enemy will kill them.

What's your opinion about K,s opinion on "Soldiers".