Even though the benefits outweighed the costs, that does not mean we simply leave Iraq once we depose the Husseins. The legal system in such situations might still require a benefiting party to compensate a harmed party. In other words, we allow one harm to occur in society because there is a greater good achieved – but then the legal system can intervene afterward to require sharing of the benefits between the plaintiff and defendant.
And isn’t that what we did in Iraq? We spent billions of dollars in Iraq as damages. We did so not because the war was wrong, but because it was right – and we shared the benefits of the war with the Iraqi people by transferring some of it in the form of reconstruction funds.