You're not gonna get far with this approach. Think about this: what was the Levant doing in Western hands in the first place? Is the Levant part of Europe? Obviously not, so why did the Romans conquer it?
There are two ways you can approach this.
#1: You can apply the good guy/bad guy approach. In which case, you will lose. Because I can just point out that the East only retook what the West took from it. The Levant is geographically, culturally and religiously Eastern territory. Don't forget that Judaism + Christianity (in its original form) are Eastern religions. Is it any wonder the Jews and Muslims of these areas welcomed the Muslims as liberators in the 7th century?
#2: Or you can apply a different paradigm. You can realize that this has nothing to do with anything other than simple geography. Any Mediterranean empire requires the Levant to secure its Eastern Flank. And whoever controls the Mediterranean, rules the region. This is why the East and West have always been forced to fight over this area. If the Asia loses this area to Europe, then Europe can project power deep inside Asia. But if Europe allows Asia to hold the Levant, Asia threatens threaten Europe. That's what it all comes down to.
Think about what happened when the West lost the Levant. Southern Europe was no longer able to hold on to North Africa. This meant they lost the revenues from Egypt + they lost trade options with the Asia + plus they lost naval supremacy in the Mediterranean. The result being that the domination of Europe once again came to an effective end.
But this time, a new development was brewing. All of this set the stage for the rise of Northern Europe. If you are of North European ancestry (especially if you are protestant) you should be thanking the Muslims for retaking the Levant. Historians have gone as far as to state that Charlemagne was a product of Muhammad (pbuh). This is all because of geography.