Syrians were under 30% of the migrants arriving in Europe from 2015-2016. https://en.wikipedia.org/wiki/European_migrant_crisis#Causes...

> The left (such as this can be described as a homogenous bloc!) was not in favour of the collapse of Syria, although they generally were against just repeating the mistakes of Iraq there. Without the attack on Iraq the collapse of Syria might not have happened, after all - it released a huge amount of arms stockpiles into the region which were taken up by ISIS.

Obama authorized the CIA in 2013 to supply the Syrian rebels with money, weapons, and training [0]. A lot of those weapons ended up falling into the hands of extremist groups like AQ and ISIL, either by "vetted" militia groups getting absorbed into larger ones or weapons getting resold on the black market. That may not have ignited the conflict, but it certainly prolonged it and contributed to the humanitarian crisis in Syria.

[0] - https://en.wikipedia.org/wiki/Timber_Sycamore