Plenty of people wearing masks aren’t handling them properly. Not using it properly, not changing the mask and replacing it, and not carefully preventing cross contamination with the changing of the mask all are risky, even if the mask is fully effective.
Today I saw a picture of Biden wearing a mask with an exhale valve!! there’s usually a reporter or three at the WH press briefings with masks with exhale valves too. And that stupid Jon Karl sits there with his glasses all fogged up — because his mask is leaking!