As a point of information,I've been looking through the complete book of Irving Berlin lyrics, and I cannot find one single lyric that could be characterized in any way as a "blackface minstrel song"--"Alexander's Ragtime Band" doesn't have any of ethnic caricatures that inhabited the "coon songs"(and many of them, such as "All Coons Look a Like to Me", were written by black composers and lyricists), and in one song that uses a form of the "c" word, he uses it as a synonym for ragtime music...given that lyrics of the time were full of this sort of thing, Berlin was actually an exemplary writer...