Because all of these things work at population level, not necessarily at an individual level.
Masks reduce the amount of aerosols a person emits, thereby reducing the distance and amount of viral particles an infected person can spread in any given situation.
As a side benefit some masks protect the wearer to an extent, particularly N95s, but the main purpose is to reduce spread from infected people in the first place.
Vaccines, similarly, are not a magic shield that protect you from even getting COVID. Instead, they dramatically reduce your likelihood of getting severely ill and being hospitalised and reduce the duration of disease therefore also reducing transmission. But that only works if enough people are vaccinated that the cumulative effect of that reduced transmission can meaningfully bring down the R0 value.
This pandemic has exposed how few people are able to consider issues or questions at a broader community level versus merely how it affects them directly.
Masks reduce the amount of aerosols a person emits, thereby reducing the distance and amount of viral particles an infected person can spread in any given situation.
As a side benefit some masks protect the wearer to an extent, particularly N95s, but the main purpose is to reduce spread from infected people in the first place.
Vaccines, similarly, are not a magic shield that protect you from even getting COVID. Instead, they dramatically reduce your likelihood of getting severely ill and being hospitalised and reduce the duration of disease therefore also reducing transmission. But that only works if enough people are vaccinated that the cumulative effect of that reduced transmission can meaningfully bring down the R0 value.
This pandemic has exposed how few people are able to consider issues or questions at a broader community level versus merely how it affects them directly.