Yup. The way it spreads is when you start breathing in air that other people have used already.
The masks can be very helpful but if they do not fit perfectly they don't prevent you from breathing in unfiltered air. It is harder to fit them perfectly than many people realize.
One doctor said the main thing a mask does is keep you from unconsciously touching near your mouth/nose area.
Saw an interesting program a long time ago. You have probably breathed at least one of the molecules of air that Julius Caesar, Jesus, Genghis Khan, etc., breathed in their lifetime.
The **** mixes.