It's no secret that Bush pretends to be a simple, God-fearing country boy. He simply made a comment, in a relatively informal environment, in-keeping with this persona. He can't dismiss creationism or he risks pissing off his base. Ultimately the best political maneuver he can make is an empty comment, that will appease his bible-beating followers, backed up with no actual action that would have invariably raised massive scrutiny over a issue he really does not care about.