Politics, power, anger at feeling oppressed, revolution. Same
   ol' reasons for every war. Focusing on religion sidesteps all of
   that. Keeps us from seeing how the west wants to divvy up
   Syria's natural and architectural resources, and ISIS is a group
   of really pissed of ppl who are blaming the West for pulling
   Saddam out of power (they didn't like Saddam either) and then
   leaving them to rot. Besides, ISIS doesn't do the extensive
   religious training that the older groups were known for.
   Religion doesn't really even play into it anymore. Maybe at one
   time (even that's historically debatable) but not now. They're
   as Muslim as Westboro Baptist church are Christian.