Let's turn the question around. Since the Bible is so much older than the theory of evolution, why do so many evolutionists resist creation?
Rom 1:20-22 For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their speculations, and their foolish heart was darkened. Professing to be wise, they became fools...Evolutionists are starving in their need to explain the miracle of creation without a divine Creator, Christians are satisfied with what the Lord provides in scripture.