Please note, it is now 1370-something according to islamic calendar, as it starts from Mohamed's flight.
During the 1370s, christians were very busy beheading, hanging and burning people, just because they had a different opinion on religion or were considered witches and sorcerers or suggested better methods to stop pestilence beyond prayers. Furthermore, in that era entire armies of christians chopped up each other on the battlefields over who was to become the next king or whether the Pope should be above the Emperor or vica versa. By now, most christian nations have grown up and no longer do such things.
Thus, I suggest islamic calendar 2000-something will see a lot of muslim computer chip engineers and software designers, who don't even know how to use a knife or an RPG (the non-dungeon type).
If you go along the lines that we should allow it because Christians did the same thing hundreds of years ago there will never be peace. for one thing it is by no means certain that the same thing will happen in Islam. The Quran has a lot of direct instructions to murder, rape, and subjugate non believers - becoming a peaceful religion would mean seeing a lot of the Qur'an as incorrect, whereas for Christians it largely meant ignoring the Old testament - which the theology itself made easy.
That said Judaism has largely come to terms with the violent passages in the Old testament, so its not impossible. The thing is even if it does happen, and you are content to let the Muslims continue in barbarism until 2700 then what's to say that some other religion won't be violent then? Will your descendants then say "oh well the Christians and Muslims used to be like this so lets give them a few centuries of barbarism?"
