For a while I assumed they lied as well. Now, looking back I'm not so sure. There really wasn't much scientific evidence of masks being effective for respiratory diseases.
https://www.sciencedirect.com/science/article/pii/S120197121... (2016) on the role of (incidental) face coverings to prevent population-level disease at large gatherings.
https://www.sciencedaily.com/releases/2019/09/190903134732.h... (2019) on the role of personal protective equipment on stopping contraction of respiratory disease (flu).
And to top it off: https://academic.oup.com/cid/article/65/11/1934/4068747 (2017) meta-analysis, including a controlled section on effectiveness on population face mask use to prevent the spread of SARS-CoV.
We had the evidence.
[0] https://townhall.com/tipsheet/leahbarkoukis/2020/06/17/fauci...