I believe OC is saying it's not a clear choice.

It seems to me like you're making a great example of the issue OC refers to.

The decision is between accepting study A (small particle assumption) and study B (larger particle assumption).

In the environment where this decision is being made, CDC is giving direction to both clean surfaces and mask up. Their priority is public health. If study A is correct, and they back it, they continue to protect against both potential pathways. If study A is correct and they back study B, they are giving people direction to stop cleaning surfaces - people will stop cleaning, and then die.

They stuck with the most risk-adverse option while the assumptions around particle size developed.

Also, it's worth noting this: scientists that study Stokes law (the physics behind where a particle will float or sink, and how long it will take to do so) aren't necessarily experts at HVAC design. Stokes law is a force balance between drag force and particle weight. Drag force is different outside, vs. inside, from home to home, even floor to floor. It can flip if you're heating a building versus cooling a building, and even flip in the atmosphere (look up atmosphere inversion).

It is a complex issue. It's not just a bunch of particle scientists realizing that they were wrong about one equation (Stokes law) in a eureka moment. It's a group of different fields coming together to refine assumptions about what the average drag force is in a social setting. No model is perfect. If science and engineering waited for models to be perfect before applying data to real world, every industry would just stop.

Yet, some of us look at the issue as black/white. "Scientists were lying to us!" "The government knew the whole time and CHOSE not to tell us!" Even in the r/science community, we can all have emotional responses to data.