The paper the Forbes article references doesn't seem to refute the idea that there wasn't a spike in "the participating demographic". They mostly focused on the

The paper the Forbes article references doesn't seem to refute the idea that there wasn't a spike in "the participating demographic". They mostly focused on the increase in social distancing among those not participating in the protests. That aside, the Atlantic article talks about outside air diluting the virus. The Forbes article you linked also talks about this.