One of my issues with Coates is that he consistently makes broad, sweeping claims without providing evidence or a compelling argument. Analogizing Israel with US slavery is absurd and sloppy, but he does it to morally guilt his white liberal audience. Liberals won't scrutinize Coates's arguments, because they don't want to be called racist.
He also never engages with the arguments Israel makes. He immediately dismisses Israel's concerns and flattens geopolitical complexities of the conflict by comparing them to southern slave owners, which is his way of delegitimizing them.
I also think he senses that the appetite for black grievances has waned, and so he's hopping onto third world anti-western sentiment because it is the new trend and keeps him relevant.