There are two ways to conceive of a military establishment's proper relationship to civilian society. On one account, the military exists in order to make civilian society possible. Like police officers, fire fighters, bus drivers, etc. the soldier is providing a public service that allows civilian social and economic life to function at a high level. On another account, civilian society exists in order to make the military establishment possible. Farmers, shopkeepers, industrialists, etc. are here to create the resources that provide the supplies that a warrior needs in order to practice his most honorable of crafts. The former conception is what's generally deemed to express the values of a democracy or a republic. The latter conception is what you have in a feudal system.
One way of understanding John McCain's oft-expressed hostility to politicians, his condescending attitude toward businessmen, and his frequent attacks on selfishness and individualism is as expressing that more aristocratic conception. That would be in keeping with McCain's family background and things like this odd genealogical note he's interested in broadcasting.