Author contends X promotes Y, because X was adamantly against Y _and_ was motivated to oppose Z who also was adamantly against Y? Huh?
This is a veiled & imputed instance of the misguided aphorism “the enemy of my enemy is my friend” - in this case, “the enemy (Islam) of my enemy (Catholicism) is my (Protestantism) friend” - no, they all hate each other.
Very true. Additionally, the author doesn't even articulate Luther's real view. The problem isn't fighting Islam, the problem is the church running a military campaign. The state bears the sword, not the church.