Islam, at its core, is violently expansionist.
Their "Golden Age" only existed and lasted because they expanded via the sword in the post-Roman/early Medieval eras -- even with the good that came with it, such as the preservation of Roman and Greek medical texts, it still came at the price of subjugation and expansionism.
When Europe got its shit together and began pushing them out/resisting them effectively, the Golden Age Islamic World basically collapsed in on itself; infighting, power struggles, theological divides, betrayals, shifts away from the arts and science, et cetera.
Only the Ottomans really managed to survive at the same level they did at their zenith, but even they eventually went into a decline over the centuries, ultimately becoming the "Sick Man of Europe".
In the modern day, Islam cannot expand like how it used to in ages past -- ISIS and other various Middle-Eastern countries have tried, and they've basically had their teeth kicked in by either the West, other Middle-Eastern Powers, or even the old Soviet Bloc (including China, and although the USSR's involvement in Afghanistan was a fucking disaster, they still bogged and tied down the Islamic fighters there).
So, now they're being subversive about it, intentionally or not -- they flee to Western nations and try to change them from within culturally and legally. Hell, the fucking birth-rates alone are going to fuck over native populations, especially if dumbasses from said native populations marry or get knocked up from these migrants... sorry, "refugees".
They don't see non-Muslims as people. Non-Islamic women are just there to be fucked and played with, with force (rape) or by consent from morons.
We see this in Sweden and Germany. 'nuff said.