This argument is only true if you push it to extreme

Not even then. If pushed to the extreme, and all/most men in a country then that country is f**ked both economically (not enough people to do useful work) and militarily (not enough people to defend the country), so it really doesn't matter if that country has plenty of women to produce babies. Any babies produced will no doubt be the babies of the invaders, not the original inhabitants.

"Protecting women" as the reason for not allowing women in the military is gynocentric myth. The reality is that the main reason for only allowing men in the military is that men are physically able to do so and generally more competent; having a poor performing military, which is what would happen if there were many women in it, is probably worse than having no military.