In counter insurgency terms it's actually quite effective provided you are sufficiently brutal.
The other way to defeat them is to outnumber them roughly 10 to 1 and starve them of their support network while creating an alternate workable system for those you can convince to join you, similar to the Malayan strategy.
Indeed a lot of people think the US Invading Iraq caused this, in fact, it was the post-invasion decision to remove Bathism and anybody tied to it from public life. So in fact, the USA dismantling the machinery of dictatorship created ISIS the irony of which shouldn't be lost on any of us.