I can never be certain whether someone is arguing in bad faith on purpose, or as a consequence of letting the Perfect be the Enemy of the Good.
Do you think refusing to visit grandma because you don't think your face mask will protect her is a self-actualization need? Sounds like a group safety need to me. Your choice of examples reads more like equivocation (conflating two things with similar features) which is generally a no-no in public debate circles.
The evidence still supports the idea that prophylaxis at the point source is an order more effective than prophylaxis at the sink, and they are not mutually exclusive. The Precautionary Principle means you do cheap things that may not work or even be necessary, but the cost of being wrong is so high that it doesn't matter how low the probability is. It's not a waste of resources. It's hedging.
If I had to be in a room with her and there was only one mask, I'd wear it instead of giving it to grandma. But why the hell am I in this situation to begin with?