jesus was middle eastern...so why is he portrayed fair-skinned?

First off, Jesus was not in this film. God pulled a prank on Evan to make him look like Noah and forced him to stay at home and work on an ark, not knowing that God was using him to save everyone in the neighborhood when the dam would break on that specific date he mentioned.

Second, Jesus was an Israelite. To call someone "Middle-Eastern" brings up images of Arabs, Turks, and Persians, not Israelites.

Third, the portrayal of him being "fair-skinned" with blond hair and blue eyes mostly has to do with artwork done in the Renaissance and Victorian Eras, and there's actually an explanation behind the Renaissance art. Back in the day, rich families could score points with the Catholic Church (which was very powerful in the 14th-17th centuries) by donating money to have churches built. Often as a "thank you" to the rich patron, artists would do murals of biblical scenes inside the churches, often making the Jesus or other biblical figures resemble the people who donated, rather than the characters they were supposed to represent.
The Victorian excuse was northern European ethnocentrism and ignorance on what Jesus would have looked like. Only a few biblical scholars back then would have had any clue of how he really would have looked, versus the majority of people in the civilized world.

americans do not know that in this region 2000 years ago the people did not look same as peoples now hahahahah