"What most people forget is that the Islamic war machine conquered most of what is now Islam militarily. One either converted to Islam or faced death"
I think you can substitute Christian and Christianity and the paragraph will the just as valid.
Surely, you don't believe all the pagans and heretics immediately and voluntarily became good Catholics following the conversion of Constantine? Nor is your statement true. The Byzantines were both Christian and Roman and used rather brutal methods to impose their beliefs on those they conquered or reconquered.
Nor were the modern Europeans much better. The Spanish treatment of the American Indians is legendary for its cruelty - but actually they were only continuing to do what they had been doing for centuries during the Reconquista. The other Europeans were pretty much the same.
If you doubt this look at how Christians treated each other during the century or two of wars following Martin Luther's declaration of independence from the Catholic Church.