For clarity, this isn't aimed at you Dry, I'm quoting to link context. "You" refers to people in general, not you specifically.
There are exemptions - at least in the UK. The problem is everyone is treated like a criminal for something that isn't in their control. It shouldn't be necessary to go through medical history in a shop to get served. Would you like to be asked the date of your last prostate/cervical exam, what contraceptives you use or the date of your last invasive procedure?
No one would ask someone in a wheelchair to prove that they can't walk up steps rather than use a ramp.
But that's the situation here. It's incredibly isolating and humiliating to have to have this EVERYTIME you want to go and get something. Many people who have exemptions are just deciding not to leave the house; if we go out, we don't stop anywhere. Think about that; you are out and want to use the toilet ... you can't because you will be abused for going into a shop or service station without a mask. Try living like that.
The disabled are being marginalized and criminalized not just by Government but by the population in general.
So if you see someone without a mask, can you at least consider they may have a (hidden) disability which means they are exempt and have a bit of understanding, rather than look daggers at them or abuse them. You can't see things like COPD, deafness, autism or PTSD; a few of the things which make mask-wearing or dealing with people wearing masks somewhere between difficult to downright impossible.