My only comment is you will win more people over by also being polite. I think to the latter person you should have smiled and said "no thank you, I don't need it." And left it at that.

If they ask questions, you can always show them a picture of one of those masks boxes that tells you flat out that they don't protect against the Rona (https://photos.app.goo.gl/sVXYQGRvieMmDBf4A)

My only comment is you will win more people over by also being polite. I think to the latter person you should have smiled and said "no thank you, I don't need it." And left it at that.