Trying to profile the mind of someone who might join ISIL?

In the 1990s before I was forced to retire with a heart virus in 1999 at age 50 I used to counsel Juvenile Offenders who had 7 felonies (none committed with a Gun) males ages 12 to 17 in San Jose, California. Later I also counseled 12 to 17 year old emotionally disturbed males and females. Of the two assignments, the first was easier because 12 to 17 year old males who have committed 7 felonies without using a gun are basically more prone to homicide whereas emotionally disturbed males and females ages 12 to 17 are basically prone to suicide.

However, homicide and suicide are two sides of the same coin so often such people are described as Suicidal/Homicidal because it can go either way at any time. So, you must realize your life is in potential danger whether you are around suicidal or homicidal people because they can often flip either way in an instant.

In thinking who would choose to join ISIL it likely would be someone:
15 to 20 years of age
never had a girlfriend (or boyfriend)
never had a job
likely coming from a conservative or rightest Sunni Family either in the Middle East or around the world

Not very realistic
Suicidal because of a lack of hope of a future
Doesn't value women other than as slaves or sex slaves
Doesn't value themselves enough to continue to stay alive
Doesn't see a future of any kind that they can want to be alive in

Lives in a fantasy and not a reality about what life really is

However, this might describe most teenagers on earth in some ways too except for the part about being raised in a Sunni Muslim Family that is conservative to extremely rightest in their views.

This likely would be a useful profiler because of the 50 to 100 recent ISIL young soldiers who told their officers they wanted to leave and were beheaded for it.

Someone who wouldn't know they couldn't tell the officers this without dying is unrealistic to a fatal degree.

If someone wanted to leave a situation like this the only way would be to sneak off and never tell anyone what you are doing and never tell anyone what you have been doing when you return home.

And unless someone was at a Lieutenant or Captain rank or above in the ISIL Army it is important to understand that joining the ISIL Army as a grunt is almost always fatal. So, unless people were either really stupid or just terminally suicidal they should have never joined as a conscious action unless the alternative was that they were captured from their village and either had to fight or become beheaded
just like so many 9 year olds to 15 year olds that have been captured wounded or alive have experienced so far.