You don't know my state. My state was a slave state. My state is a border state. My state has the eighth-largest black population in the country. My state is anything from a Northeast liberal state.
Atrios also chimes in. In Biden's semi-defense, the article is a little unclear, but I think that was in answer to a question about whether or not Biden thought he could win primary elections in the South against the region's native sons. Biden is arguing that the electorate in Democratic primaries in Dixie is heavily African-American and that, in light of Delaware's large black population, he has experience with appealing to that demographic.
Three further points. One is that if Biden genuinely thinks he's going to be president some day, he's seriously deluded, but that sort of delusion is widespread in the Senate. Second is that Atrios and Zengerle are agreeing about something! Third is that I just looked it up and, interestingly, Delaware really was part of the Southern political bloc throughout the 19th century. By the end of World War I, however, that had ceased to be the case and the state regularly went GOP notwithstanding the existence of the "solid South." Maryland has made a similar transition from being politically Southern to politically non-Southern, and a similar process is maybe taking place in Virginia as we speak.