When we talk about religious politics, there is no line between matters of faith and morals, and matters of politics and war. They're tangled together, so when talking about religious war, pope is talking about matters of faith.
Eye-witness record of what the Pope said when he called for the first Crusade in the middle east. To me it doesn't sound like a words of a guy who is going to like if somebody is going to disagree with him:
"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.
"All who die by the way, whether by land or by sea, or in battle against the pagans, shall have immediate remission of sins. This I grant them through the power of God with which I am invested."