Because by constantly touching it I'm just spreading the infections another way. Because lack of ability to concentrate while I'm wearing a mask could lead to me tripping on stairs. Because more than about 10 minutes with a mask on leaves me with a resting pulse over 100, which isn't great whether it's being caused by anxiety or something else.Imagine that wearing a face mask could save only 0.1% of air-borne infections of another person. It's much higher than that but if you as an individual had the potential ability to save just one person from getting seriously ill or worse for the inconvenience of wearing a face covering, why wouldn't you?
I suspect there is a core of people, generally young and healthy ones, for whom breathing has never been the slightest issue, and believe that everybody else is complaining about the same level of passing discomfort as they experience when wearing a mask. People aren't saying they will stay in because they want to risk the lives of grannies, or are being obtuse. They are saying that for them wearing a mask is somewhere between a serious sacrifice and medically insane.
If you are proposing measures which limit the ability of a significant proportion of the population to engage in everyday life, you should be able to offer decent evidence that they will help quite a lot, and will be strictly time-limited to the period the evidence supports. Right now we have no decent evidence and almost no prevalence. Countries where the political debate is a little more advanced than it perhaps is in the UK are starting to remove mask requirements. Now is not the time to start adding them here
