Masks have become a symbol of which "side" you're on in the coronavirus debate in the United States and for some folks, whether you choose to wear one or not says a lot about you.
If you don't wear a mask, you're seen as a callous brute who doesn't care whether you spread your germs and kill grandma. If you do wear a mask, you're seen as a quivering sheep, someone who has been willingly muted by the government.
Rationally, we know there's a lot more to it than that, however, rational thinking is rarely at the forefront when tempers are flaring. Whether or not you choose to wear a mask is an incredibly visible sign that many will read as an alliance to one "side" or the other. It's becoming almost tribal. It's like the Bloods and the Crips of suburbia getting ready to throw down at Trader Joe's.
The Mask Wearers
There are a lot of folks who come down on the side of wearing a mask. Why? Most of them say it's to protect others from them in case they're unwittingly carrying and spreading the virus. Asymptomatic COVID is a mystery. Scientists have said anywhere between 5% and 80% of carriers are asymptomatic, which really tells us nothing except, maybe you are, maybe you aren't.
The Centre for Evidence-Based Medicine at Oxford University summed it up after assembling the data from 21 reports:
What did we learn (see the table for the analysis)
That between 5% and 80% of people testing positive for SARS-CoV-2 may be asymptomatic
That symptom-based screening will miss cases, perhaps a lot of them
That some asymptomatic cases will become symptomatic over the next week (sometimes known as "pre-symptomatics")
That children and young adults can be asymptomatic
We also learnt that there is not a single reliable study to determine the number of asymptotics. It is likely we will only learn the true extent once population based antibody testing is undertaken. (source)