If you read what I wrote I said there is truth in it; undoubtedly chickens coming home to roost is an element in the rdicalisation of some people. However, unfortunately what Baz and yourself have managed to do is reduce a complex situation with roots in tribalism (Sunni/Shia), religious interpretation/politics (secularism vs Islamism) among others factors, to one thing - revenge. Also successfully generalised that an entire region with a population of roughly a quarter of a billion is full of people who are either looking or an excuse to become a terrorist, or whose ethics lead them there as they feel it is a justified course of action. Maybe, just maybe, there's a little more to it...
Start here -
https://www.theguardian.com/world/2014/aug/22/syria-iraq-incubators-isis-jihad
http://intpolicydigest.org/2014/10/20/the-rise-of-isis-who-s-to-blame/