If there was a button for, "Slap the race-card pulling asshole right in the face" I'd have picked that. Guess I'll go for "not really racist."
The way I see it, it's a guy who goes to a party that brings a CD full of music no one has heard before. He wants to DJ to play it because HE likes the music on the CD. It doesn't matter if others like what was playing already, HE wants to listen to HIS music. When the DJ tells him that he won't play the unheard of music because most people probably won't like it (which is probably true by the way) then he pulls the race card (I would be okay with this guy if he hadn't pulled the goddamned race card). The DJ's job is to play music that most people will like and to correctly judge the crowd (what kind of music to play next, i.e. slow, fast, techno, rap etc.) If he is a good, or at least adequate DJ, as you said, then he would be able to judge the crowd a whole hell of a lot better than that other guy.
The DJ made no mention of race, he mentioned that the music isn't popular.
This. Isn't. Fucking. Racist.
Second OT: Yes, people have pulled the race card on me, but most of it went along the lines of, "Oh, you don't like Obama? You're a racist fuck." and then there's the common thing I experience at Pearl Harbor when I go to pay my respects, "You did this, you damn Jap."
Now that is actually a racist comment. Jap is a derogatorry term for a Japanese person, and it is meant as an insult. There was no insult in the comment you talked about, only a knowledge of what the crowd wants.