Probably most of the "coon songs" were written by "Tin Pan Alley" type whites for minstrel shows, such as "Old Zip Coon" (same tune as turkey in the straw)& were played as a stock character theme songs, so the audience would know the stereotype of the character, without having to waste time developing the character. Kind of like when Darth Vader appears in "Star Wars", a menacing tune is played, to show he was evil, without having to go through his whole biography. Old Zip Coon was played when a character sort of like a pimp from an early '70's Blaxploitation film came on the stage in a minstrel show.
    Anyway, some "coon songs" are really songs from black slaves. Some of the ones that sound the most racist are actual black slave songs. The two that come to mind are "Run, Nigger, Run" and "Nigger in the Woodpile". They sound racist, because they use the "N-word", but that's what gives them away as genuine. The white songwriters of the 19th century considered the "N-word" as not only unsophisticated, but impolite. They substituted words like "Darkie". Unfortunately, their songs were full of ridicule for blacks, and contributed more to racism, than the "N-word" ever did. The white writers weren't trying to be politically correct, they were just trying to make themselves out to be sophisticated.
    Then as now, blacks often refer to themselves as the "N-word" in secular lyrics.
    Most of the songs commonly accepted as slave songs are gospel ones. This is because they were written down by missionaries who weren't interested in writing down the secular folk songs they heard.