Obama presided over the deaths of Eric Garner, Michael Brown, Freddie Gray, and so many other black victims of police violence which sparked very similar protests/riots and birthed the Black Lives Matter movement. Then, as now, he had the same blanket denunciations of civilian violent resistance, support for militarized police crackdowns, and anodyne advice to vote your killers away.
Those responses clearly produced no real change from those turning-point moments. Why would we hope they will in this one?