Other people wearing masks doesn't necessarily mean that everyone is mandated to wear a mask. It's not an all of nothing.
And while someone might take issue with the mask mandates which were put in place during the pandemic, it's silly to prohibit masks in response to that.
There are people who see stupid ideas (which are certainly made for all the wrong reasons), then they try to "imagine" possible ways in which it might be "useful".
Prohibiting masks would lead to the spread of disease. It's that simple. There are people who have a greater concern for their own health. There are even countries where it's not unusual for someone to wear a mask when they get sick.