The control thing wasn't necessarily directed at you, sorry for giving that impression.
Why don't they mandate masks for flu season? There's a few reasons, the biggest being that there is a vaccine, which is admittedly a best guess crapshoot for effectiveness. Next is the fact that influenza spreads through contact with surfaces extremely well in addition to the airborne droplet route that covid takes so masks would be far less effective anyway. We also understand the complications with the flu far better than long term covid complications which so far seem to involve far more organs such as the brain.
But most importantly the flu kills far fewer people annually than covid did in 2020 even if you cut the official number by anything less than a factor of 10. (despite flu deaths with preexisting conditions not being declared a hoax like people do with covid)
Covering yourself to protect from bio weapons is meant to keep yourself from being infected (despite most MOPP gear being damn near useless for it, hey guess who else got trained on that?). The mask, again, is meant to keep the already covid infected people that aren't showing symptoms yet from spreading it as much.