They are not useless for protecting the wearer, and this anti-vaxer level dangerous misinformation needs to stop. It's like saying condoms are useless for protecting the wearer from HIV because they sometimes break.
The lie that masks don't work was spread because there weren't enough masks. Sad that people are still falling for it/spreading it.
Frankly I see no downside to people wearing homemade masks.
Edit: More friendly article that references the paper I'm talking about.
https://smartairfilters.com/en/blog/best-materials-make-diy-...
If it's not 'in your face', just pretty close, then a lot of the droplets will be too small for the simple surgical mask to filter out. Especially as it leaves a lot of gaps around your nose and mouth. Not to talk about your eyes, where you can get infected just as easily. (Yes, you could wear protective glasses too.)
But... if almost everyone wears these in public places, which actually just became compulsory in Czech that should give pretty good protection to everyone (by filtering the emission of the asymptomatic infected).
And if we think about this use case, then actually it makes no point telling people that it won't protect them because if they think it will they are more likely to wear it.
If a surgical mask can stop germs from going out of the mouth, then I better hear a more rigorous reason why that same mask doesn't work in the opposite direction.
One word: leakage.
Watch this:
Healthcare - Mask vs. Respirator Video - 3M Worker Health and Safety
Surgical masks are useless for protecting the wearer from infected people, however they help protect others from an infected wearer.
If used properly, a respirator will help protect the wearer from infected people, as it will block them from inhaling virus-containing droplets.