Because the poofists erroneously believe that the most obvious explanation for observed genetic mechanisms, biologic similarities, and fossil trends contradicts the existence of their god. To come up with their alternative theory they simply toss out the most ubiquitous observation--space-time continuity. The doctrine persists despite is absurdity through cultish techniques like, "you will go to Hell if you don't believe what we believe."
It could make education a lot more straight forward though. In addition to science, you could interject religion into mathematics, and everything else. Then when it comes to final exam time you only need to know 4 answers:
Q: Where did it come from?
A: God made it.
Q: How did it happen?
A: He willed it.
Q: Why did He will it?
A: He works in mysterious ways.
Q: How do you know?
A: I let Him into my heart.
Learning is a piece of cake.
Q: How did it happen?
A: EVOLUTION willed it.
Q: Why did He will it?
A: EVOLUTION works in mysterious ways.
Q: How do you know?
A: I let EVOLUTION into my heart.
EVOLUTION is a BLIND LEAP OF FAITH.
When it comes time for the final exam, there will be only one question and one answer.