ISIS is a functionally fascist ideology. It presents the idea that everyone must purify themselves (avoid shirk) and avoid placing any aspect of life near the importance of God. Thus petty ideas such as democracy are rejected.
This stands in stark contrast to mundane life. Family, business and science all need to subjugate themselves to the state, which they refer to as jihad. (Other Muslims mean different things by jihad.) Complacency is their main enemy.
So yes, they seek conflict wherever they can get it. They seek to reduce the world to a binary set. Do what they say is right, or die.
The problem is, there will be shirkers, defined "as anyone less holy than me". They will and must kill until only the most devout person is left.
The willingness to use terror on the village level has always been an effective political strategy and difficult to deal with. It's hard to act justly against fear and intimidation, and any injustice will be used to justify their actions. When added to the inherent injustice of Western politics it becomes nearly unbeatable.
The best defense is strong historical political education. Previous Muslim fascist regimes should be expounded. It's important that people know how previous "utopias" ended. The deliberate dumbing down of our education system has to stop.
And it wouldn't hurt if we cleaned up our own political corruption. The less ammunition we give them, the better.
Unfortunately we are becoming ignorant for powerful reasons. Corruption works, at least for the corrupt. I'm not optimistic.