ISIS is just a symptom, and it is not the disease. If you really want to defeat the ISIS, then you have to take out those who are behind the ISIS, such as Saudi Arabia, Qatar, and Turkey. Even if the current ISIS leadership is taken out by the Russians and the French, the Saudis will find the replacement for them in no time.
You know what? This is no different than saying the actions of bank robbers and rapists are just symptoms, not the disease. The disease is that they weren't happy in their childhood. We need to empathize with them.
No, we solve the problem of bank robbers and rapists with police action and methods.
ISIS is no different.
There's nothing smarter or wiser in pointing at or alleging to point at "True causes," "Deeper causes" and all that rot.