Board Thread:General Discussion/@comment-122.135.62.246-20140314111723/@comment-1672596-20140314112030

It's implied midway through the game that they started phasing out to some degree recruitments by abducting enemy forces in favor of a recruiting program.

As far as their being recruited by that manner, some comments imply they joined due to some disillusionment from their past duties, and also wanting to pay off debts.