[dguaraglia]

That's an oversimplification. The first thing to consider is that there's two types of masks:

* N95 masks

* Everything else

We knew N95 masks worked because that's what professionals use in hospitals. Unfortunately, there was a shortage of PPE so telling people to buy them would put them in direct competition with professionals treating very sick patients. In April 2020 we were looking at a really bleak scenario so there was a very strong incentive to keep professionals alive even if it came at the expense of some citizens (think: doomsday scenario).

We also had no idea whether 'everything else' helped at all. Recommending non-N95 use might have given people a false sense of security that might have played against more effective measures such as extreme social distancing and self-quarantining of people with symptoms.

As knowledge improved, guidance changed. Nothing crazy to see here.