It's clearly based on what he wrote. Did you read it? He's got repressive state power on one side and repressive private power on the other and they don't really meet. He defines slavery as private/economic power, which so absurd I can't believe he's serious. But he appears to be. Same with chain gangs and the Klan.
Contra your assertion that he "challenges the standard bourgeois splitting of the economic and the political," he only inverts the split and places the emphasis differently. But the split is still there, as is the implication that the state can be a neutral arbiter between labor and capital, a thoroughly liberal idea.