That study was done in Denmark, where national guidelines on social distancing appear to be more uniformly applied & followed than in the US. It may be the case that, properly social distanced, masks add little to protection. However, given lax or non-existing distancing measures in some places in the US masks could make a larger difference. Anecdotally it appears that states with less social distancing & mask usage, on average, are experiencing worse spikes at the moment. Of course the question is whether it's lack of masks and/or distancing that's the cause. Unfortunately, lack of social distancing & lack of mask wearing appear to be closely correlated in the US so it is difficult to disentangle.
What we do know for sure is that masks can prevent a certain amount of exhalation droplets, and there are plenty of other studies that point to their efficacy [0]. Given reasonable evidence in one direction, less evidence in the other, but perhaps still a lack of consensus, it seems like taking a very simple step that could save lives is still the prudent & responsible step to take.
[0] https://www.medrxiv.org/content/10.1101/2020.05.22.20109231v...
Other decisions on things like which businesses are able to stay open, which closed etc., do seem arbitrary at points. However, if lines have to be drawn somewhere, edge cases close to those lines may always seem inequitable. Personally my main criticism is that we don't have stronger guidelines that deal with more detailed scenarios at the Fed level, that states left to their own devices are often no more consistent, and municipalities are often left to try & figure it out themselves.