It's utterly disgraceful and shameful how those who are genuinely exempt from mask-wearing are being treated, and I would argue discriminated against, for something that's completely out of their control (some of them quite literally, as disability is a protected characteristic in the UK). I do think however this highlights one of the issues that we currently have as a country.
We've got to the point where the general public perception is 'if it's not COVID, it doesn't matter', and as a society we are, quite literally, willing to discriminate against those who are the have a genuine, fully valid reason for not being able to wear a mask. The fact that, as a society, we are willing to do this to introduce a law which has no scientific basis and is entirely political which has been introduced through improper use of emergency powers is really worrying and whilst many people say 'this is for the greater good', please try and think about how you would feel if you were exempt and were, quite literally, encouraged to receive abuse from the public according to the police.
It's not right. Until we have strong supporting evidence I'll remain convinced that this law is unjustified, but NOTHING gives anyone permission to question someone's medical history, make them feel ashamed for it, or try and guilt-trip them into doing something which could make them potentially do something which is dangerous to them (wear a mask) and, quite frankly, the way this law is being handled and the comments from the police surrounding this right are simply disgraceful and shocking.