If your mask does not fit properly as you were trained to wear it, then you are actually more at risk than if you had none. And if you have a bug, you will more likely spread it around because your mask does not fit properly so the virus will escape.
This is not accurate information.
For a person trying to use a mask to protect themselves from airborne particles, the mask must fit snuggly, be worn properly. You also need to cover your eyes. If there is something in the air, any air you take in that doesn’t go through the mask will infect you.
But if you are sick, you are dumping amounts of virus into the air, a little bit in normal breathing, but it turns out, mostly when you cough or sneeze (breaking loose stuff the virus is clinging to).
FOr your air, if 95% goes through the mask, and 5% around it, you have improved things 95% by wearing a mask. For expectorant, it will fly into the mask, and be trapped, rather than flying out and landing all over things and getting in part into the air.
So, in fact, they need the masks for people who are infected. Which in fact is how most masks are used, and where they are the most useful.