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It’s possible you and I agree on some points, we just need to define our terms. If we do, I suspect we will find we agree to a degree.

Droplet transmission has two main ways of getting from the source to the new host: Direct droplet transmission where someone breathes in the airborne droplet containing the pathogen that a new host might breathe in, or droplet deposition onto a “vehicle” which is just a term for something someone might touch or come into contact with.

It is my contention that direct droplet transmission is NOT the primary way, or even a major way this virus is spread. Sure, it can and will be spread that way, but I simply do not think that is the primary way...and protection against droplet spread is only marginally improved if at all by a mask. Wearing an airtight mask with a fine filter will absolutely protect, but the stupid fabric and disposable ones are worthless. Not to mention cloth ones from Amazon, t-shirts and bandanas, all of which appear to be fine with many people.

It is my opinion that the virus is spread primarily via droplet transmission directly onto vehicles such as a door handle, a counter, a box of raisins, or a keyboard. Someone talks (they spray it, didn’t say it) and it sends droplets into the air, and those droplets settle onto a surface that other people touch and the droplet content is spread to their hands. That person then touches their nose, mouth, or eyes, and the virus is spread in that fashion.

Granted, viruses transmitted in this fashion have a lifespan-if droplets spread onto an inhospitable surface such as a hot, black steering wheel in a rented car left out in the Florida sun, that virus is going to have a very short lifespan. But if it is deposited on a cool protected surface like a computer keyboard in a library (or the credit card swipe screen inside a store) it is going to survive far longer. If the droplet is transferred to a doorknob by a janitor cleaning up at night and nobody is going to touch it for hours, that is fine...the virus will likely die on that surface. But if there is a line of people waiting to go into a bathroom at a rest area and the droplet is deposited on a urinal flush handle...it isn’t long before someone else is going to touch it and get it on their hands.

And in all those cases, people touch their mouths, nose, eyes, and face.

In the example you gave of a Choir practice, that is not a typical event. It was likely indoors, confined space, no air movement, everyone with their mouths wide open pushing air from their diaphragm, with people standing elbow to elbow. (This is my opinion)

And these “aerosols” coming out of people’s mouths are not uniform. I used to have to use an aerosol with radioactive isotope in it for diagnostic purposes, and you had to have the machine set just right. If you set it too low, you don’t get enough aerosol (isotope) into the lungs. Too high, and the droplets are larger and deposit more easily (and undesirably) in the bronchial areas instead of further down in the alveoli areas.

In both cases, these were generally pretty controlled aerosol droplet sizes.

In the case of someone talking, they range from being great big globs you see exiting someone’s mouth as the person across from them winces, all the way down to droplets not seen unless the light is just right, and even then.

It is a wide spectrum. At the larger end, those end up dropping due to gravity onto a surface that is touched by human hands. At the smaller end, those may be inhaled and infect someone. If that person is wearing a standard mask, bandana, t-shirt, underwear on the head with ears in the leg holes, some smaller droplets can deposit on a mask, but many more would go in or out around the edges. Not worth a cup of warm spit. Or, they are.