Because God would seem more the vicious jokester for writing the book of Genesis and describing the creation the way He did if He really made the universe over 15 billion years through evolution. There are many Christians who have submitted to pop science and believe that the universe must be old. If we see starlight from 10 billion light years away then the universe simply must be 10+ billion years old.
These people feel that God is a trickster for saying the universe is young but making it look old. They fail to consider that when God made Adam He made him an adult. Scully would swear that Adam was 25ish years old 2 seconds after God brought the dust together and made him.
Because God would seem more the vicious jokester for writing the book of Genesis and describing the creation the way He did if He really made the universe over 15 billion years through evolution.
Well, (a) I disagree that that is the bigger joke. Even assuming the divinity of the Bible, I would regard the existence of facts and observations in the natural world (the handiwork of the Creation) to be stronger evidence for the work of God than a human-copied, edited, and transcribed account. If a picture is worth a thousand words, how many for the planet? But I am still left that God has intentionally deceived me.
(b) If I reject the inerrancy of Genesis (it is divine allegory, or inspirational, or human created, or was intended by God for a specific audience of nomads 4000 years ago, or it was a amalgam of myths, etc.), then the question of trickster-ness vanishes. That seems to be the easier answer: if the facts don't fit the description, it makes more sense to reject the description than the facts.
(c) Finally, your only justification for evolution being wrong is that it disagrees with your religion? I thought the whole point of these crevo threads was to debate the natural evidence (and as the article at the top of the thread points out, the appropriateness of the subject for public schooling, among other things). You seem to have conceded that most important of points: that creationism and the rejection of evolution are entirely and exclusively based on your own personal religious views, and are not scientific questions at all, and that by extension, any person who did not share your literalist religious interpretation would have ne reason to question evolution.