It used to be a valid question because the culture around masks was different before covid (where I live). Now people are more informed about types of masks and how to utilize them properly. If someone asks now, I just inform them; but the taboo is no longer really a thing. Some masks can protect others, some masks can protect both user and others.

Most I deal with now is someone pushing their ideologies about "not wearing one if you're not sick". And I'll try and inform them if they care to listen. My wife is immunosuppressed and I work as an ICU nurse; I don't play with fire when it could possibly end with me losing her, over something as simple as being aware. And neither of us have gotten covid yet, so we're doing something right.

Misinformation about masking and general public hygiene is it's own pandemic