Loads of variables as to why
@General Zod was unfortunate enough to catch the virus. Glad your getting well and on the mend, scary stuff

Neil, with respect, you come across as something of an Enigma. You are categorising all masks.....
Certain masks / respirators with the correct P3 - N95 rating wore correctly with other PPE is effectively better than no protection at all. In fact, I don’t think you need to be a PhD to work this out. It’s kinda common sense......The NHS and 1st line teams are dawning this equipment as it’s rated to offer some protection. It was proven in 2003, think tanks reflective post SARS outbreak......
What overwhelming proof do you have to contradict this?
Have you ever entered an NBC chamber with chemical gas and taken a few deep breaths? With a fit for purpose respirator you will have no side affects....
Take the mask off and repeat, see what happens.....
The correct respirator/ mask wore correctly with other PPE does offer protection.
Wrong mask, wore incorrectly with no other PPE or poor avoidance techniques then that’s a different story.