The general public's perception of the politician is what got many of them their jobs in the first place. Relatively few voters resumes could stack up to the types of people who go to Washington.
In terms of common sense and basic morality, its another story.
Yes, everybody is fair game for criticism, and some of the folks in Washington could very easily and accurately be called bumbling idiots (such as people that fail out of divinity school, get kicked out of school for plagiarism, etc. and others who provide numerous demonstrations of idiocy). Often I hear politicians make statements that are so outrageously false that I must conclude that the person is either an unconsionable LIAR or a blithering idiot. Such politicians often lack any impressive intellectual accomplishments.
Condi is not above criticism, and some of her decisions or the outcomes of her activities as Secretary of State can certainly be questioned. But to refer to her as a "bumbling idiot", given her unquestionable intellect and her many accomplishments -- from academics to politics to the arts -- does nothing to support one's criticism of her.