The entire premise that platitude is based on is false. Approaching the platitude directly will not convince a JW. In order to make an effective argument, a JW needs to look beyond their false premise. This is not always easy, but there are ways to do this. There are even university courses that teach this type of abstract thinking, but it is a discipline, and requires a certain amount of mental practice.
Apart from the obvious fact that other faiths such as Quakers, have similar dogma, the key here is help a JW see their premise is wrong. The following lines of argumentation need to be applied:
a. Many individuals have a strong belief in some sort of pacifism. A religion is not necessary for this position. Are individual JWs more inclined toward this than the average person? Are they not simply following someone else's, (their group's), conscience on this matter? Which person represents somone standing on higher moral ground, a follower or someone making the choice out of their own conscientious decision?
b. As Cofty mentioned, is pacifism even a virtue? Even as a JW, I knew that protecting my family and loved ones knew no limits. If someone were to put them in harm's way, it is game over for them. Can this not be extropolated to my neighbors? Community? Country? It is really about protecting what is ours, or even protecting someone in danger. It is a necessary evil at best. No sane person wants war.
c. Look at the conflict within the congragations. Why does that conflict even exist? Does it originate with the individual, or might the environment play a bigger role than one thinks?
This line of reasoning will not convince someone overcome with cognitive dissonance, (any believing JW), but it will possibly plant a seed of thought that may germinate later in life.
d4g