Dylan uses ain't instead of isn't and instead of them is to show that he is not prejudiced. Bob When Bob Dylan wrote the song, he put some words to the melody of an old slave song called "No More Auction Block". Dylan took the song to the nightclub Gerde's Folk City in Greenwich Village, where he was about to perform it. Before playing it, he announced, "This here ain't no protest song or anything like that, 'cause I don't write no protest songs".
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