Islam is growing, why?
Basically, imho it's the concept of evil that plagues Christians - they cannot find a satisfying answer to it that also does not change their concept of god ie all good, knowing, powerful.
Muslim theologans dissolve the problem of evil straight away as they believe evil is part of god also - a way of learning, essentially.
I would like to point out that if they believed in conversion the Isrealites would behave like isis in a heartbeat - they have and do, only in their case the issue at stake is land.
The problem is the same - the 'god given right'for or to do something!π‘