Bush is not clever enough to come up with the vast number of one-liner screw ups that he spews out nearly every day. Presidents have writers who provide them word for word content - how does he manage to so consistently twist those pre-planned words into a hilarious one-liner? He's not sharp enough to do it. It's as if those writers are writing his screw-ups into his speeches.
So people focus on the delivery of Bush's speech instead of the content of his speech, and focus on the messenger instead of the message. "Look at the silly puppet and ignore that guy behind the curtain!"