Early in the pandemic, virtually all the major health orgs spread the message "masks for the public don't work". Of course, the real issue was that there was a valid fear that there would be a run on masks and not enough for healthcare workers. There was never any significant evidence masks for the public don't work, on the contrary there was at least some flu-based evidenced that they were beneficial, but at best you could say "we don't know".
So I'm very sympathetic to the authorities trying to give simple messages, but in the end the original guidance really bit them in the ass and made a lot of people lose trust. I wonder if the simpler message could have been "don't use a mask, because it means nobody will be left to treat you when your nurse/doctor needs a mask".