Or maybe it is not weird at all for Cheney to reasonably think that the press wouldn't believe anything he said.
If Cheney said that the sky was blue, the press would argue with him until night time, then scream about Cheney being a liar.
When the VP made that comment, I saw it as a sort of "mental shrug" like "So?" People who have no sort of life are still picking apart every syllable of the VP's interview.