Bombs, bullets, bang-bangs, and their production, involve economic-cycle wastage. Some trifling examples chosen at random for contrast:
If it was liquor, or bonbons, or feather hats, people would be stimulated, nourished, or socially involved - the consumption is not altogether wasteful. These products may even stimulate further economic activity: The drunk buys a hangover remedy, the overweight diet plans/pills, the showoffish... sells the old hat (eventually - or donates it to someone who will) and buys another. At very least, these products may, by giving people contentment/happiness/excitement/pleasure, produce the economic stimulus of buying more of them... By way of wanting to be able to buy, & working toward being able to; job stimulus is also present here. The ultimate justification of all economic activity is both ideal and practical: the good is being happy with products or services, the practical aspect is the economic stimulus. In an ideal product, both are present in one.
When a bomb has gone boom, something needs rebuilding. Someone needs a death or disability pension ( - "The government can pay," is a nice way of saying that higher taxes are a consequence of the waste of material and life).
Both ways, more expense is made.
[ A drunkard occasionally destroys things, but a bomb does nothing whatever else; at miniumum, it destroys itself, completely. ]
Or: Higher taxes without product are the ultimate expression of waste. Income taxes being what they are - in a democracy [-income taxes in a tyranny would be *very* different-] even the rich pay for the wastage, even though it be in the next electional cycle.)
The bomb-maker gets a job, but his product... doesn't economically benefit anyone else. It can't be resold usefully... especially after usage. Not even in one's own nation. Rebuilding costs may be expected to be shouldered by the conqueror, too. And the loser... has wasted lives and expenses. Surviving soldiers need retraining as well as training: are they going to handle an M-16 rifle, or crawl through the mud usefully, here at home?
(War materiel usage is a waste, in short, except to a limited extent in its favoring of what used to be called 'Merchants of Death'... a conversion to raw effluents and a wasteful flushing out of the economic cycle, into nothing or less than nothing.)
Expecting making war to stimulate the economy - without anything else to help it - is a good policy for the narrow-minded fool, the narrow-interested profiteer (another species of man-ostrich with a tendency to avoidance of a more extensive viewpoint), and above all the chronic polyanna - because being defeated in war is economically hazardous! . . . slightly.