Well, there are studies suggesting standard surgical masks are at least partly effective against viruses. In one study, they were showed to be equally efficacious against influenza as FFP3, probably due to incorrect donning and doffing. See this review.
https://www.cebm.net/covid-19/what-is-the-efficacy-of-standa...
In primary care staff. Up close with sick patients. And then... as you mention, partially. In a large building where people are keeping their distance, and not coughing... asymptomatic or not infected (hence not viral shedding) partially goes to no effect at all.
The evidence that N95 is the same as the pointless blue mask isn't surprising, neither are designed for viruses. I doubt that the blue masks are getting incorrectly installed, it's healthcare professionals, and the mask has no face mate other than the nose metal.
I’ll be honest, I don’t really follow your argument. If they are partially effective, it helps reduce the R value, which prevents transmission on a population level. If it is partially effective with those with a high level of viral shedding, I don’t see why it would be less effective for those with lower viral loads.
It seems reasonable to assume that masks will help to reduce transmission, until further robust evidence shows they don’t. I mean what is the alternative?
Additionally, interesting article suggests that salt infused masks have increased efficacy against viral particles. Perhaps using salt infused masks would be even better?
