Yes, it spread by the sword, rather than love.
Why is the Pope not denouncing islam as a devilish trick?
Maybe because it would accelerate the actualization of the bloodshed to come in Europe.
Not personally being Roman Catholic, I can’t “pontificate” on why the Pope of the Roman Catholic church isn’t proclaiming something like this.
The previous one appears to have made the mistake of getting too chummy with Islam in an attempt to find common ground of morality with them. An infamous picture shows him kissing a green-covered copy of the Koran. I think that approach, however well meant, reduces Christianity to a morality story, and inadvertently invites moral relativism.