Right - they thought that it was only spread by symptomatic carriers so they advised people that were buying up the limited mask stockpiles to not buy them. It turned out that they were wrong, and that asymptomatic spread was already happening so they revised their advice and by early April were encouraging people to use homemade masks (to preserve hospital supplies of surgery masks and N95s).

I don't think their credibility should be negatively impacted for updating their advice with the latest science. It's a shame people are reading it in the most negative light possible.

That’s painting it in the most charitable light. For the first months of the pandemic, they specifically said “don’t wear a mask because current evidence is that it does not spread airborne and most likely infection vector is contact with a contaminated surface, don’t bother with masks but wash hands and scrub surfaces.” It wasn’t about asymptomatic cases not being transmitted in the air but in general about the coronavirus not being “primarily” transmitted via the air, which would have been patently false even at the time, except for the “primarily” weasel word. (You can look at the archive.org snapshots for the CDC website.)

As a scientist, my answer to “should we wear masks?” wouldn’t have been to deflect to contaminated surfaces - even setting aside that subsequent research showed that to be largely a non-issue.

They said a mask won't prevent you from getting it or prevent spread. Just wash your hands. It didn't make much sense to me that respiratory virus wasn't transmissible through the air, but I washed my hands like they said. The Trump tapes prove they knew about its air spread as late as early February. Who knows how many lives this cost? You could argue it may have saved some as well. You can't argue we weren't lied to.