Blaming black people solely for all their ills is low-hanging fruit. It's easy to beat down a perpetual, raciali bottom caste. What I don't think some may realize is that "crabs in a barrel" statement in regards to black people actually reinforces anti black racism imo. A barrel is not the natural habitat for crabs. If you have a pot full of crabs in boiling water, and they claw at each other to escape, do you think they're doing so because they hate each other, or because the water is hot and killing them?
James Baldwin said it best when he said to be a black person in America and relatively conscious means to be almost always in a state of rage. We have been in the boiling pot of white privilege for half a millennium and there's still much work to be done.