1. Influenza infections are almost always symptomatic. People who are sick, know they're sick and can avoid others, stay home, and in some cultures, also wear masks.
2. The flu is nowhere near as deadly as CoVid.
3. It's not that I don't believe in charity, it's that One's charity is limited by time and resources. You can't give more time than you have or donate more than what you possess. Doing something as simple as wearing a mask in public is not the same as charity. It costs nothing and requires no sacrifice. It's an act of kindness.