That's not what I said. Is there evidence that wearing a mask significantly protects the wearer?
N95 masks and better - yes there is. Surgical masks and worse - does not help significantly.
Though as I mentioned previously - effective also means protecting other people. And there is evidence that masks significantly protect for that.
The CDC is telling everyone that masks are not effective, when if fact they are. They tell people not to buy masks, but if they get a fever, cough or other symptoms, they're not able to buy a mask anymore, and if they're infected they will be infecting others. And even for people without symptoms (but are potentially infected), if the CDC was prepared they would have enough masks stocked up for everyone.