If you read the translation of the Holy Quran, you will understand the reason why there are so many Muslim terrorists. For example, if you read this chapter of the Qur'an, which I have linked here, you will see that Allah has repeatedly ordered to fight with polytheists and people of the book (Christians and Jews) (exactly verse 28).
Discussion
I wrote the verse number wrong. Verse 29
I know the religious motivations, but I’m presenting a case of why it imprints on all of islam as a whole.
Yes, I agree with your opinion. The people of the Middle Eastern countries are still dependent on tribes (although not as much as in ancient times) and this is separate from the dependence on Islam.
Yes tribalism existed long before Islam. But Islam comes to reinforce a posteriori whatever tribal ties that were in place. Also the religion itself doesn’t favor individualism. It’s always the believers vs everyone else.