Well, this "science in action" garbage is certainly this week's attempt to save the institutions from self-immolation, but it simply doesn't hold water:
1. The initial statements were not guesses. They were an accurate summary of the state of the scientific literature at the time and were presented as such ("there is no specific evidence", "there is some evidence to suggest the opposite").
2. The later change, which occurred with whiplash-inducing speed, wasn't based on any new evidence or studies. That's why Fauci had to come up with this story about how they'd been engaging in a noble lie: there was no new evidence for him to point at.
3. There is now clear evidence that mask mandates don't work, namely the real world data, yet recommendations have not changed and all this new evidence has been ignored.
Specifically, if large-scale mandates did work then it would be clearly visible in the case curves of each country that introduced them, by definition, because creating clearly visible drops in those curves was the only reason they were introduced. Yet no such drops are visible. You can't look at a country's data and work out when masks were introduced or removed, it's impossible, people have tried. Thus mask mandates failed on their own terms and no further studies or experiments are actually necessary to answer the question of whether they're effective.
I don't really know why you're trying to defend "science" in the abstract like this. COVID science is the work of specific groups of people, it's not an abstraction, and it turns out to fall far short of the lofty standards we were taught to expect at school. COVID science in the real world is riddled with obvious hypocrisy and contradictions, routinely ignores or even rubbishes any evidence that would undermine collectivist social policies or make scientists look bad, and just in general is a sad joke. Arguing that this obvious failure is actually a success, and this is what all science looks like, can only make things worse by harming trust in other groups of scientists with higher standards (e.g. maybe physicists?).