No, they don't. In a trial setting the standard is beyond a reasonable doubt. Meaning the accused is given all possible advantages before he gets convicted. In congress that standard simply isn't applicable. Because it simply tries to ascertain the most likely rendition of facts.
Nitpicking is focusing on a small detail of a testimony that is contested. And trying to use it to invalidate the entire testimony. She said that she heard something from someone else. Wich is indeed hearsay. On the other hand, she did so by citing names. Names who can testify. At the moment they aren't. I think that is telling. Substantial parts of her testimony weren't hearsay at all, and yet all of you seem to insist that Hutchinson isn't reliable while at the same time being against people testifying who can corroborate or dispute.