Those that defend a biblical monomgamy have to twist and contort to do so. Those that jump at the chance to condemn slavery as immoral also frequently refuse to condmen homosexuality with the same vigor even though it is condemned unambiguously and frequently.
IMO, slavery is an undesirable condition, but I sure as sh!t would enslave any enemy to the USA that I could, whether is was here, or there, making them work for my ease and comfort.
Would you turn down the opportunity to enslave AlKaeda?