Are you trying to describe monogamous societies or polygamous ones?

OP is asking why Western societies frown on polygamy, but you respond by talking about the strategic value of having more readily available cannon fodder - I assume in polygamous cultures, because that’s the only thing that makes sense. A monogamous society, assuming relatively equal M/F birth rates, would have LESS available available military men, by your own description.

I’m not sure how that answers OPs question unless you’re saying that Western societies frown on polygamy because it was SEEN as just a tactic to raise armies?

Agree in principle. Haven’t seen Yesterday, but Across the Universe soundtrack is my go to Beatles cover album.

I believe the word you’re looking for is “comic”