Nonsense. That type of attitude comes from a certain pompousness that certainty is better than honesty. Science is all about evolving knowledge, as time goes on, you learn more, you reassess your assumptions. That's how science works.
Take Fauci's comment that there was no need to make day-to-day changes -- that statement came in late February. At the time, our best knowledge was that there were only a handful of cases in the entire country. So yes -- no need to make day-to-day changes, when there are only 15 cases in the entire country. And when he learned there were thousands and thousands of cases -- that advice changes.
And one reason vaccine development went faster than expected, it because of how uncontrolled the virus has been. Studies take much longer when a virus is well contained -- because not enough people are getting sick quickly enough, to measure. The "silver lining" of how totally out of control Covid has become, it greatly accelerated testing.