That is not the reason that soldiers are often the salt of the earth. Indeed Roman soldiers used to kill the salt of the earth who were early Christians, persecuted by salaried soldiers for the sake of righteousness. As Jesus said whilst sermonising upon the mount:
Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.
It's strange that the phrase originally meant the tiny thing (the early church) that made the world palatable to God, but now means the common majority. The important thing is that government campaigns against salty foods are almost certainly blasphemous; or as St Paul put it:
Let your speech be alway with grace, seasoned with salt, that ye may know how ye ought to answer every man.
And I think we have demonstrated that it is. The word salaam, though, has nothing to do with salt. It's Arabic.