I was using cloth masks in mid-April. I started using crude folded bandannas cut from a T-shirt around 1 Apr, ~2 weeks after my state issued their stay-at-home order. Some kind of covering was required if you wished to enter grocery stores at that time. By ~13 Apr I was able to find and start using cloth masks with ear holders.
"Strong science"
Are you are saying there is no published research on the use of cloth masks?
http://files.fast.ai/papers/masks_lit_review.pdf
From the abstract of the same paper:
This paper was published in April 2020. At that time a mask recommendation was considered scientifically valid.
https://www.ucsf.edu/news/2020/06/417906/still-confused-about-masks-heres-science-behind-how-face-masks-prevent
https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-mask/art-20485449
I doubt the Mayo Clinic is going to recommend cloth masks without having seen some metrics that support their use in reducing spread of the virus.
https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html
https://www.kpax.com/news/how-cloth-face-mask-reduce-covid-spread
Yeah, there is no scientific evidence at all.
Are cloth masks in and of themselves a complete solution?
NO
Is anyone saying they are a complete solution?
NO
Who is (generally) saying that they should not be used?
(In my opinion) Those using political, rather than medical agendas as their driving point.
Once again - the idea is to slow the spread as much as possible in order to buy time for proactive quarantining rather than bulk quarantining of everyone.
Europe has used cloth masks in conjunction with social distancing and heavy testing as they have decreased their rate of active positive cases. They still have hot spots flaring up, so we must continue to work for a vaccine. Masks are meant to help us buy time.
Most of the rest of the world resumed sports sooner than the US, and has been able to start allowing attendance at some of those sporting events (AFL). The US may try that in September with college football, but, based upon current infection rates, it will probably hasten the shutdown of the season unless things seriously improve, such as an order of magnitude or more reduction in daily positives.
Bottom Line:
In my opinion, the United States missed the opportunity to sufficiently contain the initial wave of the virus during the months of April/May/June, which would have lowered the daily new positive rate low enough that a feasible college football season could have occurred in the Sep-Dec time frame. At this point, evidence would indicate that we will not sufficiently lower counts anytime in the near future, unless we become more diligent about mask use. So, if a season does occur under the current situation it will probably be greatly disrupted by outbreaks, with many teams playing (at most) 3 or 4 games this fall.