But some things have no potential for harm, and they should be recommended with higher priority than something that could be harmful at the same likelihood of efficacy. It seems to me that the recommendations are mostly based on how well it provides a predictable financial benefit to a specific investment (mail-order, pharma, etc).

They supported lockdown of the healthy when no major western country had it as a tool in their pandemic plan and specifically recommended against it.

Masks have been recommended heavily since the beginning without good evidence that they are effective. [0]

https://www.medrxiv.org/content/10.1101/2020.03.30.20047217v...

CONCLUSIONS Most included trials had poor design, reporting and sparse events. There was insufficient evidence to provide a recommendation on the use of facial barriers without other measures. We found insufficient evidence for a difference between surgical masks and N95 respirators and limited evidence to support effectiveness of quarantine. Based on observational evidence from the previous SARS epidemic included in the previous version of our Cochrane review we recommend the use of masks combined with other measures.

We've had a lot more information come out since March 2020.

The Bangladesh study is a particularly good one, demonstrating changes in disease prevalence even with less than half the population following masking recommendations: https://ncrc.jhsph.edu/research/the-impact-of-community-mask...

The bangladesh study showed that groups of people that are spending large portion of their days inside small huts will benefit from mask. One particular area was also mosques which has a large number of people coming and going, with people being near each other indoors.

Mask makes great sense in specific contexts. Near vulnerable groups. In tight spaces and areas of low ventilation. In areas where a large number of people meet. The further away from such areas, the less evidence we get.

There is a reason why conferences is generally associated with people getting sick, while the same can't be said about the beach.

Sure, skip the mask at the beach. We've known outdoors is likely quite safe due to ventilation for a long time now.

The Bangladesh study is likely informative in busy grocery stores, retail, offices, schools, etc.; certainly more than just "inside small huts".

> The Bangladesh study is likely informative in busy grocery stores, retail, offices, schools, etc.; certainly more than just "inside small huts".

The study did not show that. It was a study conducted in rural areas of Bangladesh, areas with small villages of huts and some mosque. Those are quite different from a large city mall and office complex. Schools are a even more complex since while children has a significant higher rate of getting sick in general, the transmission rate between children and adults is significant lower. The ruling on school lock downs and mask in schools has yet to be established.

We can look at specific examples. If you are on a packed plane then a mask is pretty good idea. Traveling on a bike then it is unlikely to do anything good. Mask in crowded open floor plan with bad ventilation, yes. Mask in personalized offices with good ventilation, no. A conferences, yes. A school, maybe. A bench, no. A large grocery store in off-hours, less likely. A crowded grocery store in rush hours, more likely. In a public bath house, the data seems to indicate no.

Things that seems to correlate with transmission rates seems to primarily be about: distance between people, ventilation and humidity, practicality of staying isolated at symptoms, age and risk groups. Raise any attribute of those to an extreme and one can get data that either prove or disprove masks as effective.

Weird to pick a release from March 30, 2020. A modern review[0] concludes:

Our review of the literature offers evidence in favor of widespread mask use as source control to reduce community transmission: Nonmedical masks use materials that obstruct particles of the necessary size; people are most infectious in the initial period postinfection, where it is common to have few or no symptoms (45, 46, 141); nonmedical masks have been effective in reducing transmission of respiratory viruses; and places and time periods where mask usage is required or widespread have shown substantially lower community transmission.

The available evidence suggests that near-universal adoption of nonmedical masks when out in public, in combination with complementary public health measures, could successfully reduce Re to below 1, thereby reducing community spread if such measures are sustained.

[0]: https://www.pnas.org/content/118/4/e2014564118

This paper’s from March, 2020?

Note that I said "since the beginning".

Which is also incorrect; the US Surgeon General tweeted masks "are NOT effective in preventing general public from catching #Coronavirus" in Feb 2020, and Fauci said "There’s no reason to be walking around with a mask" in Mar 2020. Recommendations were frequently firmly against masking early on.

And the fact that that was 1) motivated by other concerns (principally: ensuring availability of then VERY scarce masks for medical personnel and first responders), 2) bad advice, and 3) backfired very badly has been public record since ... March of 2020. See Zynep Tufekci's "Why Telling People They Don’t Need Masks Backfired"

Given that there is indeed a mask shortage and that medical workers absolutely do need these masks more, what should the authorities have said? The full painful truth. Despite warnings from experts for decades, especially after the near miss of SARS, we still weren’t prepared for this pandemic, and we did not ramp up domestic production when we could, and now there’s a mask shortage — and that’s disastrous because our front line health care workers deserve the best protection. Besides, if they fall ill, we will all be doomed.

If anything, a call for people who hoarded masks to donate some of them to their local medical workers would probably work better than telling people that they don’t need them or that they won’t manage to make them work. “Look, more masks would be great. We are doing our best to ramp up production. Till then, if our medical workers fall ill, we will all be worse off. Please donate any excess — maybe more than two weeks’ worth per person — to your hospital” sounds corny, but it’s the truth.

https://www.nytimes.com/2020/03/17/opinion/coronavirus-face-...

Oddly, it seems to be those who still most strongly resist wearing (or bully others for wearing) masks who seem to recall those first few weeks of ill-advised messaging.