Personality

That is the answer.

How do groups like ISIS in particular, and the JW as an aside, pick recruits?

There are a variety of Personality Types, a few described by Meyers-Biggs.

And, as you might expect, there are also a number of personality disorders.

Google: anagrams jung sufi

The middle east or ANE is/was a hotbed of one-upsmanship, gaining the advantage in the caravan trades.

The secret of cults. like ISIS and the JWs, is a foundation of unhappiness and dissatisfaction in those that they target. Sexual repression is an effective tool for religions to use in controlling their "catch." Sexual repression might just be an unintended consequence of personality.

TRUE BELIEVERS lack Critical Thinking Skills.

I will pick an example in which I have no investment. If you BELIEVE vitamin C can cure/prevent cancer, then you have a weakness others can exploit. If you THINK vitamin C can be beneficial based on a preponderance of evidence from your own research, then you have a strength.

My opinion on BELIEF reflects that of the Buddha 2,500 years ago.

cults make liberal use of many influence techniques

Individuals may also have an unreasonably high opinion of themselves and feel that they have been held back in professional or social situations. Religions offer many fabled rewards, from 72 white grapes to inclusion in the 144,000.

Zen offers NOTHING. It may be your best choice.

No need to go door-to-door with comics or go to extremes with bad behavior.