Not a full study, but when people were kneeling to draw attention, it poled at about 30% for 60% against 10% undecided. When people burned down the police precinct in Minneapolis and documented the unwarranted police violence, it polled at about 60% for and 30% against.

I don't know why, but as a general rule with people, if it bleeds, it leads. And that's what's worked here.