I'm trying to imagine a minstrel show with black elves. And failing.
Answering a question about whether a drow costume would look like blackface at Halloween Costume -- drow or blackface, one person answered, "I showed my wife (who is black) your post and she said she wouldn't consider it blackface either, that the idea wouldn't occur to her, unless you were also dressed as a Vaudeville act. We live in South Carolina and I don't know anyone that I would think would have the blackface allusion as a first impression. My kids wouldn't even know what blackface was if we hadn't explained it to them one time while studying old films as part of their homeschool studies. "
Where Will Community Rank On the List of Recent Blackface Stunts? - Movieline: "Will the sight of Ken Jeong in blackface push things a bit too far?" The writer doesn't know about drow, but does explore the question of blackface with examples of actors in dark makeup.
Blackface - Television Tropes & Idioms: "Due to sensitivity over this issue, particularly in America, any attempt by a non-black actor to play a black character will usually be labled by someone as outright blackface, even when it's really just a Fake Nationality." Someone should add: This will probably happen on Tumblr or LiveJournal.
ETA: Just for the record, I can imagine fusing a minstrel character with a dark elf. That may be the only explanation for Jar Jar Binks.