It's not solely influenced by their books "FYI"; you seem to have a limited understanding both of the wider political and psychological influence.

How jihad works

Yes, the Quran does call for jihad. However, there are several types of jihad.

One is jihad al-nafs, which is the process of learning the teachings of Islam and patiently bearing the difficulties of introducing people to the religion.

One is jihad al-shaytaan, which involves handling your doubts and avoiding what is evil.

These are the two types that are obligatory.

The other types (against the nonbelievers and hypocrites) can be interpreted as being obligatory for the community as a whole, but the first two types of jihad (struggle) are seen as the truer and most important, and everyone is obliged to do them.

Political influence

Islamic extremism was virtually unknown fifty years ago. Western intervention in the Middle East, the homeland of Islam, over the past century has made people angry.

Look at what we did to Iran: https://en.wikipedia.org/wiki/1953Iraniancoupd'état#Blowback

This attack on Iran's democracy resulted in people becoming angry and embittered at the West. They rallied around their heritage -- which happened to be Islamic -- as a way of distancing themselves from those who had interfered and overthrown their democratically elected Prime Minister. Not only this, but the Iranian way of life was under threat; for example, the veil was banned and the calendar had been changed to suit the West. Most women at this time didn't wear the veil (https://seanamirhayes.files.wordpress.com/2014/04/scn 0085.jpg) but Iran saw it as an attack on their heritage by Westerners who just wanted their oil.

The Islamic Revolution was a direct result of Western interference. Iran went from being a democracy to a theocracy in a few decades.

Still don't think there's any political aspect to it? Osama bin Laden is quoted as having said after 9/11 that attacks would continue until the "infidel armies... have left the lands of Mohammed."

When people are resisting colonialism etc., it is not uncommon to rally around the national religion. Sometimes the religion is used as a way for people to justify their resistance (I'm not justifying the rise of Islamism, but this is how it happens). Islamism is extreme Islam, politicised.

If you think it's just Islam that's the problem, think of Buddhist extremists in Tibet who are using their religion as a form of resistance. Or the IRA who used Catholicism to resist the British.

tl,dr; Places like Iran were fine until we intervened. The Palestinians were peaceful until the West plonked Israel on top of them.

Psychological influence

A lot of jihadis in the West (or those who go to fight in Syria) are young men and second or third generation immigrants. They may or may not grow up with Muslim teachings, but they are generally not raised with extreme views. This is why a lot of friends and family are shocked when they do something terrible in the name of Islam.

Unemployment among young, working-class men is high. Many extremists are unemployed. As second or third generation immigrants, they have probably experienced racism but don't feel so strongly attached to their original culture. This cultivates a sense of resentment, and they may revisit their cultural roots as a means of resistance. Some just want excitement or heroism, hence why they go to Syria.

This is in no means a justification. I'm just pointing out that to put the blame on religious texts is ignoring the wider picture, and is a contributing factor as to why current efforts to curb extremism are not working.

There's 3: 3 million Muslims in the US where's all the bombing taking place in the US Jeffers ?

Why are you calling Italy 'my ' country ?

In my bio under country I have Italy why do you presume that's my country ?