My argument is for asymptomatic folks who are vaxxed.
So the vaccines were initially only study to prevent illness in the vaccinated.
That has really good data. It continues to do so.
A secondary question was if your vaccinated could you still replicate virus particularly in your nose, that uses some different initial antibodies, and then transmit it to the unvaccinated.
Throughout the spring there became developing data in that particularly showed decrease viral loads in the nose of those that are vaccinated. Due to this and probably also due to some social pressures, mask were removed if you're vaccinated.
For all the reasons you're imagining and suggesting here.
As the Delta variant became the predominant strain, We saw an increased amount of transmissibility. There was an outbreak in the Northeast and they found that vaccinated individuals had unexpectedly high viral load and that there's reason to believe that the vaccinated individuals contributed to the actual outbreak by transmitting virus to unvaccinated individuals.
That's what made masks come back.
There are a couple of other studies in England That suggest this is not generally true in that in fact being vaccinated may continue to significantly reduce transmissibility and vaccinated individuals even with the Delta variant.
We don't know.
We do know that we have massive hospital overruns happening across the country right now.
So masks are a cheap intervention.