They may block bacteria but that is not proof that they block viruses.Off topic:
I did a science experiment to see how effective face masks are at blocking bacteria. I sneezed into a petri dish with a mask on, and sneezed into one without a mask on.
The results were interesting after a week.View attachment 2891137
This is a sneeze with a face mask on. Only one bacterial colony after 1 week of growth.
View attachment 2891136
This is a sneeze without a mask on in the same amount of time. See all those tiny white dots? That’s bacteria.
Face masks may be annoying, and we may not like wearing them, but they sure do block bacteria and viruses well!