You seem to be falling into the Historian's Fallacy[1]. (decision makers of the past viewed events from the same perspective and having the same information as those subsequently analyzing the decision.)

At the time COVID data was sparse and masks were seeing a shortage so that healthcare workers could not get enough to perform their duties. Was this the correct action, perhaps and perhaps not. You may also be correct with your conclusion but your recommendation is not been vetted by healthcare professionals and so there may be very large gaps in your knowledge (unknown unknowns) that make your conclusion seem like a no brainer to you.

Perhaps what you can do is take down the post and share it with a professional to see if it makes sense and if are any issues they see.

Lastly, medical advice comes with legal implications if someone follows it and comes to harm. You may be opening yourself to legal risk.

I know you've got the absolute best intentions, but it's our responsibility in this age of tech to be rigorous with truth and what we choose to broadcast to others.

[1] https://en.wikipedia.org/wiki/Historian%27s_fallacy