But we all live with some level of risk. Keeping the risk level at or near zero isn't realistic, or something that most people want. We cross the street, travel in cars, etc.
I find it weird that PyCon had a mandatory masking policy, when medical conferences staffed by doctors and disease experts don't have such a policy any more. And I'm guessing that PyCon's policy was made by well-meaning people who aren't doctors or medical experts.
My suggestion -- and yes, I wrote this in my PyCon follow-up survey -- is that our masking policy follow whatever the CDC, AMA, or a similar body is doing for its conferences at the time PyCon takes place. If the experts require masking, then we should do so, also. And if they don't, then we should encourage people to mask if they need or want to, but we shouldn't force it upon everyone.
In other words: PyCon should make decisions about the conference and Python-related things. Medical decisions should be left to outside experts.