Debator:
We can toss different translations of the verse around all day, but the Greek word in the text is a form of sarx, which does not mean "flesh/world," it means FLESH. Any translation that uses "world" there is paraphrasing. This is important because Paul constantly pits the terms "flesh" and "spirit" against each other. In this chapter, Paul is not discussing whether it is appropriate for Christians to join the military service of various nations. He is talking about a spiritual type of warfare. True, we don't "wage war according to the flesh" when we "destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ" (v. 5). That is not the sort of warfare where weapons of the flesh are effective (even though, as someone noted above, the WTS has expressed a desire to kill physically those who leave its ranks). FOR THAT PURPOSE, "the weapons of our warfare are not of the flesh but have divine power to destroy strongholds." This is spiritual warfare being discussed, not the defense of nations. These remarks by Paul have no bearing on whether Christians might serve in the military.
To interpret the text in the way you are trying to do, we must ignore all of the other arguments I mentioned - and I notice that you did ignore them.
Why didn't John the Baptist take advantage of soldiers asking him what they should do to tell them that their profession was unacceptable to God?
Why wasn't Cornelius told to remove himself from any form of military service, even inactive status, before being baptized, as would be required today of anyone who wanted to become a JW? For that matter, why does the policy of the WTS regarding those in military service not conform to the biblical model as demonstrated with Cornelius in Acts 10?
Additionally, Israel was a warrior nation. They fought God's wars and were commanded many times to engage in military action. So it does not appear that God is adverse to His people engaging in military service. Now, it's true that Israel had a special relationship with God as His people, and that Christians are not under the same covenant as they were. Nonetheless, for God to go from REQUIRING His people to engage in warfare to PROHIBITING the same, it seems to me that there should have been a very explicit command and explanation somewhere in the New Testament - just as we are explicitly told that the laws about Sabbath observance and unclean meats no longer applied to Christians. But there is no such reversal with regard to military service.
Again, I don't expect that every Christian will agree with me about this. I can certainly understand why some Christians might take a pacifistic position (though JW's claim not to be pacifists). However, this is clearly an area where there should be room for personal conscience, and it is the Watchtower's unreasonable control, to the point of breaking up families over this issue, that I find to be morally repugnant.