There's an additional element which played a part - the power of ritual.
Performing a ritual is a way of binding people together (as religions have known for thousands of years). The first rule of ritual states: The more pointless and absurd the ritual, the stronger its effect on binding people together.
Wearing masks, in particular, was a pointless ritual. But it performed its duty in the sense that it bound the People of the Mask into a stronger group, and increased their allegiance to the herd mentality.
Yup! When we played organised football back in the 1950s, someone would kick the ball, and we would all chase after it. Not the greatest of tactics there.
That bit about training instantly reminded me of a film also. No idea what it was called, but it consisted of two sets of foot soldiers, from opposite sides, ready to swap blows. However, one side didn't do the usual, and charge a couple of hundred yards to engage. They just stood firm, waiting for the enemy, to run double distance.
The two opposing Generals were on their horses, observing and chatting, when the charging occurred. One General complained to the other that it was not fair, that his warriors would be well out of breath when the two sides met for combat. The other General just shrugged and said; 'new tactics'.