The response to this way of thinking is "we didn't know stuff we know now back then", "we learnt things as we went along, and updated our models, advice, warnings"

The mask thing is hardest to justify as the whole of Asia was saying they worked back then and the reasons given for why they said "they don't work" back then is "well they had to lie because we didn't have enough masks to go around and we didn't want you to panic" which admits a lie.

Then back then they said "masks do work, but we don't have enough" which implied they were lying initially but can be explained by saying " we didn't know the full facts" again.

So an outsider might see these messages as a kind of benevolent way to effect behaviour change amongst PPE shortages and to stop panic, and another sees behaviour modification as lying and manipulation common in conspiracy theories.