It's the risk of having any credibility to burn. In contrast, crackpots spreading rumors about the efficacy of zinc or the logical impossibility that a mask won't stop the virus but does stop oxygen from reaching the brain have no credibility to lose, so their observable percentage loss is lower.
It might be false but it's not logically impossible, for example if you were breathing through a tiny but non-filtered hole the aerodynamics could make it very difficult to breathe while allowing aerosol droplets through in small quantities. In fact, there is a good lesson buried in the insanity, which is that having something over your face, even if it is making it harder to breathe, might not be perfect protection.