I doubt his neighbors knew whose music he was playing. The two plausible explanations I see as likely:
* The music was cranked up so damn loud that the neighbors would have called the police were the song, "Sing, Sing, Sing" or the "1812 Overture";
* "Biggie's" music, like much rap and hip-hop, is laden with foul language, misogyny, and violence; the music was loud enough for the words of the Gangsta Ballads to be understood, and the neighbors didn't want their children's ears and minds filled with F-Bombs and brags about what the "singer" does to his hos and wants to do with police officers.
Both is highly likely. The tell-tale that the reason the police were called was how obnoxious the guy's use of the music rather than his favored artist or style was that neighbors called. A neighbor might be racist enough to complain because (s)he hates rap-hop, whose artists are mostly black. But when multiple neighbors call it's because the dude was being obnoxious (possibly intentionally, since he's now race-baiting).
