Hypothesis:
Some say that Fauci pled the 5th and tempts contempt because of a need to protect against a perjury trap of state or even international charges…BUT…
What is he's trying to preserve his testimony because it would bring down a F-ton of other people, and he can't do that until that testimony is unencumbered by any claim against it being permissible in the future. Perhaps getting him for contempt is a way to give him some time in prison, a la bannon/navarro model.