This all goes back to the time of the Crusades, and the reason that a Crusade was even started.
It was started as a dispute over territory, which quickly escalated into a difference of doctrine, and rationalizations by each side why the other side should totally exterminated.
Centuries of nearly unspeakable brutality visited upon the other side proceeded from that really bad quarrel between what had been neighbors, if somewhat uneasy with each others’ presence.
Without going into a detailed history of the various Crusades, let it be said that the push back and forth between Islam and Christianity has undergone a sea change, initiated from within the Christian side, that there should be negotiated peace. While the Christian leaders may have entered into these negotiations with some expectation of a mutually acceptable outcome, the Islamic leaders have been adamant in that their demands were not negotiable, or negotiated on such terms as to be wholly favorable to their cause.
Again and again, the West, representing the Christian point of view, has been suckered and sandbagged, when it became apparent the Islamic leaders were not negotiating from “good faith”, but only as warfare by another means. They lie, feeling no remorse that the lies only masked later treachery or hid future preparations for open and active warfare. To them, it is OK to lie, to gain their objectives, in the expectation it is easier to gain forgiveness (or surrender) than to ask permission.
Islam has been at war with all non-Moslems since Mohammed moved his “congregation” to Mecca in 622 AD.
The history of Islam is a history of warfare and conquest.