Judith’s actions were during a just war, true, but she was not commanded by the Lord to kill a man while he was defenseless.
God’s way is the right way, always! I am not refuting that, simply saying that his way isn’t always love and mercy only, but also just. Sometimes the less than nice and peaceful ways are mandatory. Since God doesn’t give audible commands in every instance of life, I cannot say how we as Catholics are commanded to do this. Certainly not every Catholic would have this calling. We have Catholic soldiers, Catholic police, Catholic FBI…and again, “illegal” isn’t always sinful, especially when sin is a guaranteed “right.”