Its not that hard if you think about it. Islamic fundamentalism is basically composed of Islamic radicals like ISIS. What can you think of that ISIS has done post-WWII that matches up with the guidelines of Islamic fundamentalism?
Islamic fundamentalism is a political and religious ideology, backed by the Sharia (Islamic Law) that coordinates various aspects of Islamic society. The fundamentalists' discourse on their main objective is to return to the primordial principles of Islam when it began with Mohamed in the seventh century in Saudi Arabia. They believe that present-day Islam has been diverted or corrupted by the adoption of principles contradictory to original identity and extreme attitudes have come to pass.
One point that shows a cause and effect relationship of the rise of Islamic fundamentalism in the Middle East since World War II was the dissolution of the Ottoman Empire and the caliphate of Mustafa Kemal Atatürk (founder of Turkey), some Muslims felt their religious identity threatened by the influence of Western ideas, as a consequence of the economic and military domination of Western countries. During the 1960s, the predominant ideology in the Arab world was Pan-Arabism, which placed less emphasis on religion and engaged in the creation of a secular socialist state, inspired more by Arab nationalism than by Islam. One of the leading figures in this ideology was the Syrian Michel Aflaq, the founder of the Baath party, who studied at the Sorbonne in the 1930s, times of ideological struggles in Europe. He was fascinated by the Nazi Regime, the Pergomanism of Adolf Hitler. He coined as few as the ideology of Pan-Arabism, which seeks to unite the Arab-speaking countries under a single command. Several governments based on Arab nationalism have often struggled with problems of economic stagnation and social conflict. Some Muslims blame the ills of their societies for the influx of "foreign" ideas. A return to the principles of Islam is perceived by them as natural healing. A persistent Islamic theme is that Muslims are persecuted by the West and other foreigners. In this general background, fundamentalist ideas have developed in different settings.
