Parenthetically, have any of you read the relevant Wikipedia article? Did you find it lacking? if so, in what way?
I don't expect people who think nothing of regular beheading and ethnic rape to be well represented by a Wikipedia article, for various reasons.
For starters, I would like to know how varied their motivations are and how the emphasis are distributed. Do they see themselves mostly as nationalists seeking independence, or as warriors for Islam? Is ethnical hostility a significant motivator? Do they actively seek to oppress minorities and religious groups, or was that a situation caused by circunstance?
How many of them are just adolescent thugs looking for a thrill and lacking an environment to set them straight? To what extent is being in ISIS a choice for the average member? Is it realistically possible to convince them out of their current ways, and if so how? How much of an effort has been made to both create and communicate alternatives to their apparent future of killing and dying with no real alternatives to speak of? How much resistance do they have against hearing such messages, and for what reasons?
Lacking good evidence otherwise, I think it is fair to assume that any given human group would rather not be remembered as hateful, fanatic butchers. Sure they have shown evidence of dehumanizing their victims in order to justify themselves, but emulating their example is not something I want to pursue.