1. https://pubmed.ncbi.nlm.nih.gov/24229526/ - this is a paper from 2013 testing the efficacy of homemade masks versus surgical masks finding that both have some effect but surgical masks are better. If you look under "similar articles" you'll find 4 there about masks reducing the spread of airborne viruses from before 2020.
2. https://pubmed.ncbi.nlm.nih.gov/20584862/ - demonstrates 2010 study showing the strong effect of N95s against small particles in the breath (on which the virus is borne) and comparing it to homemade masks. Concludes homemade masks would offer marginal protection. Again, in similar articles you'll see another three from before 2020 on the efficacy of masks.
Masks were well and widely known to be useful at slowing the spread of airborne contagions - especially N95 masks. People knew homemade masks had some effect too.
There was probably good reason to want to save N95's for medical professionals. There was no reason to say masks weren't helpful for the general public though, that was an absolute lie. Fauci and others had all the information they needed at the start of the pandemic and could have said "Masks are useful, that's why we need the best masks for our medical workers. We've put together information on how you can make homemade masks that are X% effective and what you can buy and use."
That's not evidence, but a claim that you provide no evidence for. Even if he was wrong, you don't have evidence that he made a mistake or that he lied.
> Masks are and were well understood to be useful in mitigating the spread of airborne contagions.
IIRC, most medical experts agreed with Fauci at the time. The analysis of someone on the Internet doesn't mean much.
Do you have have any evidence of this?