I believe this is primarily a narrative that was invented to prevent a temporary shortage of masks for health care workers. This may be a noble cause, but it's still a lie. Surgical masks reduce the probability of infecting others if you have it (maybe without knowing), and correctly used N95 masks drastically reduce the risk of getting infected.

There is a reason why South Korea officially distributes masks to the public. Everybody in China and Japan wears masks, too.