In the early 1900s, most of the Arab world was under the rule of two empires. The Ottoman Empire and the British Crown. The common Persian and Arab suffered greatly under this rule. The Arab world was fractured. It consisted of tribal monarchies and warlords. As a result of the Great War (WW I), the Arabs were organized to fight the Turks. They enthusiastically joined in that fight, thinking and being promised self-rule. After the war ended the "promise" was not kept. After long negotiations, some warlords and the Arab monarchy were granted lands. However, These warlords and monarchies were tyrannical toward their own people. This manifested itself as a deep festering of distrust and hate. The west needing oil placated to these tyrants, causing hate among the people for anything western. Religious Islamic fundamentalist (that had been marginalized by the tyrants) seized an opportunity to gain the trust and loyalty of the Arab people (who were devoutly religious). For decades these common people have seen more and more oppression by the monarchies and tyrants and the also what they perceived as encroachment by the west. This idea was heightened by religious propaganda.
Now what exists is disenfranchised people being motivated and driven by decades of oppression, Islamaphobia, religious propaganda. This gave rise to terrorist groups that seek power, not justice. Ironically it also gave rise to populace nationalism. Basically Fascism.
The cure is respecting the basic Arab/Persian not buying into populace nationalist propaganda.
We must understand that this terrorism isn't Islamic based at all. Also vilifying a whole religion and people is nothing more that Fascism. All it could serve is creating more terrorist.