From an evangelical point of view there shouldn’t be a problem at all. Considering the evangelical doctrine of all past present and future sins are forgiven by Christ, that must include then as now (the context of the quote being the islamic murdering of christians and burning of churches, beheading etc.) the current endorsement of war against those same powers for the same actions going on today. Or rather a modern day crusade.
However I think it appropriate to cite the parts obviously omitted in the above post
“Although, O sons of God, you have promised more firmly than ever to keep the peace among yourselves and to preserve the rights of the church, there remains still an important work for you to do. Freshly quickened by the divine correction, you must apply the strength of your righteousness to another matter which concerns you as well as God. For your brethren who live in the east are in urgent need of your help, and you must hasten to give them the aid which has often been promised them. For, as the most of you have heard, the Turks and Arabs have attacked them and have conquered the territory of Romania [the Greek empire] as far west as the shore of the Mediterranean and the Hellespont, which is called the Arm of St. George. They have occupied more and more of the lands of those Christians, and have overcome them in seven battles. They have killed and captured many, and have destroyed the churches and devastated the empire. If you permit them to continue thus for awhile with impurity, the faithful of God will be much more widely attacked by them. On this account I, or rather the Lord, beseech you as Christ’s heralds to publish this everywhere and to persuade all people of whatever rank, foot-soldiers and knights, poor and rich, to carry aid promptly to those Christians and to destroy that vile race from the lands of our friends. I say this to those who are present, it meant also for those who are absent. Moreover, Christ commands it.”
For reference, Islam took over france and spain before they were stopped. As I understand the objection to the above it is either that the current conflict in the middle east should be allowed to kill all the christians and not attempt to stop them (thus tacitly endorsing ISIS), or that killing after becoming “reborn” isn’t forgivable, thus calling evil a doctrine which claims all future sins are forgiven by Christ.
I find it an interesting conundrum none the less
Peace and God Bless