@AutoTripper
If you don't use other people's masks and you either clean them regularly or replace the disposable variety, you're not going to get sick.
You might as well argue that labs have confirmed there is athlete's foot present in a certain number of socks.
Maybe you should be exempt considering your condition, but (honestly) I don't think there is any compelling evidence that masks reduces oxygen intake. It definitely makes it harder to breathe even for me - and I don't have any respiratory problems - but I don't feel like my oxygen levels are restricted.
If people like yourself with medical issues don't wear masks, that's fine... but why encourage people without medical problems to exploit legal loopholes and not wear them just for the sake of it? I get that you don't want to wear them, but what do you gain from convincing others?