And how are parties, restaurants, sports any different as infection-breeding grounds than protests? They may be held indoors, sure, but to an incomparably lower extent than mass outdoors gatherings (during which people often got packed like sardines judging by the photos from Washington and other places).
And I disagree about your common sense statement. Just like the virus is not sleeping during late-night parties, it is most definitely not sleeping during social unrests either. Common sense also tells me that scholarly works can be subjective when dealing with sensitive issues like this one (as in made to support certain claims whatever they may be). You can get persecuted for any kind of claims against these protests. This is America we are talking about, after all.