Occasionally an exceptionally boisterous fan can be heard on TV heckling athletes. Rarely is it ever as clear as this presumed Spurs fan who had some unkind things to say to the Clippers.
Athletes are probably well accustomed to hear that they suck. Having someone say "you're not that good" is an interesting twist. Poor J.J. Redick took the brunt of it despite not even being involved in the play.