... and it is...
" then why even have the crusades during the middle ages?
That answer is easy. The Crusades were defensive warfare for the purpose of re-taking lands of the Byzantine Middle East which had been invaded and occupied by the Islamic aggressors, securing Christian places of pilgrimage, and lifting the Islamic yoke from the shoulders of the indigenous Christian people.
The Crusades were, I say again, defensive --- comparable to the landing of the Allies at Normandy during WWII.
The real problem here was not the Arabic word "Allah" , which indeed had pagan origins as did every word for God in every language.
Names with 'el' as one of their components were common in the Near East in the second millennium BC. Linguistic cognates include ancient Semitic El, biblical Hebrew Elohim (God or/of gods), Arabic 'ilah ("a" god), Arabic Allah ("the" God) and biblical Aramaic Elah (God).
In the Mosaic period, 'el was synonymous with the Lord who delivered the Israelites from bondage in Egypt.
Pagan words for God were ALWAYS adopted by Christians when these pagan areas were evangelized.
Terms first used by pagans:
The Koran is the problem. And, more than anything, Muhammad himself--- a wicked, bloody-handed, slavemonger, lecherous, war lord/false prophet --- is the problem.