I think I made most of my points in the Eyes of Texas thread, and while I generally don't enjoy getting into these sort of discussions as they tend to not get anywhere, for the sake of being concise, I don't think that a song being performed blackface or in a minstrel style inherently condemns it to being a racist song.

If a modern performer were to continue to perform it in blackface style then sure, I could see it, but if they sing the lyrics in a normal manner and perhaps take out any of the potentially questionable lyrics to some otherwise-unoffensive songs then many (if not most) of the songs are simply songs about life, farming, or comedic and not inherently racist or offensive.