"Yes, I am sorry that you have been told over the last year that masks don’t reduce oxygen, by emphatic and dogmatic people, but the fact remains that oxygen deficit during mask-wearing is very thoroughly established in peer-reviewed clinical data. Here[1], here[2] and here[3], for example.
And yes, surgeons also suffer from deoxygenation.[4] Excess of carbon dioxide, as it accumulates inside a mask, also is a mild poisoning of the entire body, and this is also established in clinical data. [5] [6] So if you demand that a child, a worker, a traveler, a consumer or anyone else wear a mask, you have been demanding that they mildly poison themselves.
I know this is vexing for some to read, but you cannot inflict harm with any moral authority, and you need to stop that now that you know it’s a problem, if you want to be able to live with yourself, or to exist peacefully with a good conscience."
https://www.technocracy.news/noted-physician-makes-definitive-moral-case-against-mask-mandates/