...Jews and Arabs lived side by side in Palestine for centuries with levels of violence between the two nations much less than what we've seen since Zionism began in Europe about a hundred years ago...
Mere coincidence.
Muslims worldwide have been largely under the heel of European colonialism and imperialism since the 1700s and 1800s, until the end of WWII, which is still within Living Memory, and which coincides with the advent of the State of Israel.
Freed from British and French and other European colonial status, and once again (sometimes, for the first time) empowered to govern (and arm) themselves, both dictatorship and democracy have rested very imperfectly upon the trouble brow of these Muslim-dominated states - several of whom are mere fabrications of departing European masters - and these States oftentimes end-up reverting back to an imperfectly-reproduced Islamic Fundamentalist mindset and Sharia and its derivatives as the only familiar and viable alternative.
Islam is a Warrior's Religion rather than a Religion of Peace, and they have been pressing that advantage since the 600s, and throughout much of history since that time, although their empires and caliphates have always degenerated into licentious and effeminate and ghostly echoes of their more manly albeit barbaric and savage founders and predecessors.
Freed from British and French and other European colonial status, Islam at-large is re-awakening and re-arming, and making tentative but increasingly-serious probing sorties against The West (modern, secularized Christendom).
Western support for the State of Israel is only the excuse du jour - or, more accurately, only ONE of an ARRAY of excuses du jour, used by the Militant Element within Islam, to rebuild and test its strength and to probe for weaknesses in its age-old and mortal Enemy - The West - a.k.a. Christendom.
Portraying Western support for the State of Israel as the primary cause of Islamic militancy and violence is a blinkered, myopic, short-sighted and disingenuous tactic designed to (1) divide The West from Israel and (2) take our attention away from the broader Islamic re-awakening and re-militarizing that has been underway since today's range of Islamic states achieved their independence from their European colonial masters.