Ludwig von Mises argues that: "There is no kind of freedom and liberty other than the kind which the market economy brings about. In a totalitarian hegemonic society the only freedom that is left to the individual, because it cannot be denied to him, is the freedom to commit suicide." 

I think it is a fair argument that what we have created, through direct and indirect intervention in the Middle East, are totalitarian hegemonic societies.  

Our occupation of Iraq has used price controls, inflationary monetary tools, destruction of local economic infrastructure, as well as outright death and dismemberment of the civilian population, all to keep Iraq under US control.  Hence, the creation of a totalitarian hegemonic society in Iraq. As such, individual Sunnis in Iraq are employing the last physical freedom available to them, suicide to eject the enemy invader-occupiers.  

Robert Pape's brilliant thesis regarding suicide terrorism could be considered an iteration of Mises' argument: 

"The central fact is that overwhelmingly suicide-terrorist attacks are not driven by religion as much as they are by a clear strategic objective: to compel modern democracies to withdraw military forces from the territory that the terrorists view as their homeland."