Yes, terrorism tends to be reactionary, but ISIL is certainly not born of a reactionary fight against the West. It's born of a reactionary fear of oppression of those of the Sunni faith by those of the Shia. Having the west "stop throwing punches" won't make this problem go away.
It's born of the ambitions of Abu Bakr and his schism with Al Qaeda backed by a healthy whollop of Sunni Islamic fundamentalists wishing to recreate their ideal world.
And before you say that "the Middle East can deal with its own problems" remember that this entire refugee crisis is brought out of trying to accomplish just that.
More complicated than that. Destroying Libya, Germany's encouragement of immigration and the insufficient response to the ME in addition to Islamist movements from Pakistan to Somalia - the refugee crisis is for another thread because it is one vast one.
I can guarantee what little effort the West has put into stopping ISIL and ISIS has not directly caused the massive volume of refugees to flood into Europe.
The West has put a great deal of effort into destroying ISIS. I am quite annoyed when everyone assumes that since there's no reported success nothing is being done. I was absolutely appalled when people in the Europol thread were saying France, Britain - even America were sitting on their bums doing nothing when their soldiers were still fighting everywhere across the world and still in Syria to boot. ISIS's land grab was reversed because of the West's air strikes. The Kurds don't want to stretch themselves out too far beyond their control and the Iraqis don't have the capability or will to fight alone. And so the West can keep killing ISIS soldiers and to that end drain its manpower and eliminate threats to the West (most recently two planning attacks on the UK were killed and Jihadi John was also killed with these air strikes) but Bagdhadi merely changed strategy and adapted. Again, like I said a year ago these attacks would happen because Bagdhadi said it himself. Create volcanoes of jihad on your homefront and tie up foreign nations with hesitance, fear, confusion and demoralization, to expand the perceived control of the state across the world and improve brand image and ultimately lead to more success against the sustained air strikes. One of the criticisms Obama levied on the Russians was that they would alienate themselves from the Sunni world by siding with the Shiites, and to that end most Western countries have large Sunni populations of their own which makes things complicated too, in addition to usual war weariness (in regards to committing large scale ground troops. Special forces roaming around assassinating ISIS leaders is not enough to fully eradicate the whole militancy).
The air strikes used to be hampered by the fact that the militants could move between Syria or Iraq and state aircraft could not cross the border. Now they have no safe areas, so they choose to attack everywhere and be as formless as possible. The great Western powers all have elite police units and security bureaus to counter this to minimize damage on home soil, and the attacks on Paris have not caused France to cease operations. But putting a stop to ISIS? Even a state of total war would from the USA, China, Russia, Britain, France, Turkey, Israel and Iran would take some time to kill them all - they're very slippery, and very eager to take advantage of any foreign weakness.