Oh, sure. Totally agree. But, again, it's not like the issues with Drow are subtle or require really sideways views in order to get offended.
Like I said, if you're going to have evil, beautiful (since drow women are always depicted as hot) matriarchs that hate men, worship a black widow spider demon, and then enslave men, I'm thinking that it's not too hard to see the message here. It's right freaking there. In big, bright, neon letters. Add to that the fact that they are all elves in blackface, and well, it's not exactly a stretch to see where this might be problematic.
Thor got away with it because, while the dark elves were, well, dark, there are no "light elves" in the movie to contrast with. You don't get the "light=good" thing going. And, most people can make the connection between dark elves and fairy tales. Not a big issue. But, had they used D&D drow in Thor, I think there would be a much larger negative reaction. Maybe not. Maybe I'm worried about nothing.
But, surely you can see why this might be an issue.