The only reason why people join DAECH, vote for Trump or Le Pen in France

Inequity!
The concentration of resources in the hands of fewer and fewer people.

You wonder why people are desperate enough to risk their lives, joining Daech?
Nothing to do with religion.
They're just poor and desperate.

The 1% richest people own 50% of the world GDP.
The 10% richest persons own 87% of it.
The 20% of richest persons own 94,5% of it.
The 50% richest persons own 99% of it.

The trend is rich people are getting richer; poor the people are getting poorer. And this trend is exponential/accelerating. If you're part of the 50% poorest people who have nothing and have less every year, yes, you get extreme.

Another example from an excellent source of info, CFR, in Congo:
"Lack of economic opportunity boosts recruiting for armed groups, and competition for land and other natural resources often leads to violence."

You wonder why people vote for far right party in France?
Nothing to do with racism.
People are just poor, afraid of getting poorer, move out from middle-class. 

The 1% richest people own around 40% of the French GDP.
The 10% richest persons own 50% of it.
The 60% richest persons own 98% of it.

Far right promise them jobs and the return of "the good old France". They buy it.
Other parties don't really focus on inequity and did not resolve the inequity challenges for the last decades, German press spotted it.

And why people vote for Donald Trump?
That's the same story.
They are afraid of being "declassed", poorer... and they're right. The US middle class is getting poorer and die younger, even white people. Guys got a Nobel prize, doing a research proving this.

Conclusion
This figure always used in media is "the 1%". This group is basically the bad guys team, responsible of everything. People love to have a black sheep to criticize.
But the issue is not the richest 1% or the poorest 1%, the problem is the concentration of resources in the hands of fewer and fewer people.

There are tons of reasons why inequity is getting bigger.
There are tons of ways to reduce inequity, solve this resource concentration issue.
It could be the greatest challenge of the next decade.