1. people suffering from PTSD who have lost much of their capacities to think clearly; specifically, part of butchered Sunni community in Iraq following the sectarian war fuelled by US invaders after years of deadly sanctions (they also include former members of Saddam's secular stasi-equivalent http://www.spiegel.de/international/world/islamic-state-file...), and some of the Syrians going through Assad's butchery. This is no different from how a bunch of peaceful villagers turned into brutal group that was Khemer Rouge (http://johnpilger.com/articles/from-pol-pot-to-isis-anything...).
2.A tiny western group who are largely clueless about the world (almost entirely about religion), seeking certain warped sense of glory: http://www.theguardian.com/commentisfree/2014/sep/04/jihad-f...
On a different note related to welfare, Saudis are probably not that worse off in certain ways: any (poor) Saudi is eligible to receive funding/stipend from his/her government for studying in world's top universities, unlike many rich capitalistic states that are effectively no less of an oligarchy.
Given the turmoil that has lately (and long been) transpired in the form of militant experiments and perceived revolutions around the region (and the globe), the tradition that promotes mass-education, deeply-rooted revival and collective rectification doesn't seem to be a bad idea as the feasible choice for societal betterment.
This is not how it works out. Please don't make assumptions about issues which you don't know about.
The Saudi government is a legitimate government, regardless of their current shortcomings, or things that they can do better. They govern a stable country, and are keeping peace and stability within the country. It is prohibited to overthrow them.
Here is just one example of how ISIS is being denounced in the Middle East (unfortunately, there are spelling and grammar mistakes in the captions): https://www.youtube.com/watch?v=JQ2HlIYRvCM