Just as those of the Islamic faith would assert that there would be more worship of Allah, had the crusaders not come.
And so goes the ebb and flow of theistic history...
I never attempted to justify the crusades. Guess it's easier for you to put up a false argument when you can't refute a point.
Let's try it again. If Christians were allowed to legally proselytize in islamic occupied lands, initially, more people would be given the opportunity to exercise God-given free will , and ultimately, fewer people would be born into islam (read: satanic deception).
Looks like some (little g) god is afraid of the competition.
Therefore I assert that islamic religious beliefs are not as you suggest just "a geographic or familial accident", but is in reality, brainwashing by a psychotic demon.
Okay, if you still can't see the difference, try the analogy of a dictatorship (Islam) and a democracy (Christianity). Islam teaches that apostates, (Moslems who decide to leave the faith) are to be killed. See if you can find that in the Bible.