Interestingly, I didn't see from the summary that they were controlling for the conditions for which individuals were being treated with HCQ and the impact they had on their lives.
If people with Lupus are treated with HCQ (they are) and people with Lupus are often forced to make behavioral changes like staying indoors and out of the sun and avoiding physically demanding activities - which they are - doesn't it seem reasonable that those lifestyle changes would result in fewer SARS-CoV-2 infections?
FWIW, I'm very much open to the idea that HCQ may be a viable treatment for COVID-19. I've not kept up with the clinical results since it became a political issue, but it originally seemed to be a promising avenue of research. Once Trump started talking about it, it became all but impossible to find data about its effectiveness that wasn't obviously politically motivated.
This paper doesn't appear to be politically motivated... but it also doesn't appear to provide strong evidence one way or another.