In the end, like all good Abrahamic extreme religious fundamentalists, they desire to help bring about the Apocalypse. In between now and then they intend to instate extreme Sharia Law for Sunnis and execute or enslave everyone else. The rank -and-file do not intend to survive long term. They intend finding glory denied them in otherwise unfulfilled lives. Their leaders, however, do not necessarily buy into this holy martyrdom -- they simply know what "records" to play for their minions. They don't plan on going down with the ship -- their minions can die glorious deaths, while they "capitalize"....
It behooves us not to engage in calling
them unIslamic, when in fact, they are over-the-top extremely rigid
fundamentalistic Islamic (as our own extreme Christian fundamentalists
are extremely pre-Old Testament Christian). Both groups are insane and dishonor their
religions; but, that is somewhat irrelevant in dealing with ISIS. What
is needed is for us NOT to militarily intervene in Syria, but to make
sure Iraq is able to defend itself and to integrate Sunni and Shia into
Iraqi governmental rule in the process of fighting against a common
enemy, the ISIS.