This article talks about their fear that masks would cause reckless behavior being a main reason they told everyone they were useless, but another one I've hear

This article talks about their fear that masks would cause reckless behavior being a main reason they told everyone they were useless, but another one I've heard in interviews is they thought medical staff needed them more and the public could not be trusted not to hog them if they told the truth. Pretty clear that waffling was a total disaster with serious harmful effects.