Whatever Happened To Common Sense?

My knowledge of the sizes of certain substances was very limited until I decided several years ago to do some research. After finding several web sites that explained the size of different substances in microns, then a question popped up about wearing masks during the pandemic.

I read an article on a government site that stated regular masks don't work if you're ever involved in a situation where you are surrounded by smoke such as a house fire or wildfire. After learning about the size of smoke, bacteria and viruses another question became very evident. 

If a virus is much, much smaller than a smoke particle and you can inhale those smoke particles through a regular mask that means you can inhale even more particles from a virus through a regular mask. 

Why are the government and health organizations telling us to wear a regular mask and in some cases a scarf for protection when they know that a virus can get through them and into your system?