Apple had made the decision weeks ago, the company told Rolling Stone, while Pandora has been refining how it deals with artists accused or guilty of 'unacceptable conduct.' Spotify pulled R. Kelly's music for violating its new policy regarding 'hate content and hateful conduct.' In essence, all three frame their decisions as removing their tacit endorsement of musicians without, well, removing their content entirely.
To be clear, Spotify has done the latter, yanking white supremacist music off its platform entirely after Charlottesville. But removing content from official playlists is a sort of stopgap reprimand to distance it from the brand. Their approach seems to compromise between permitting speech without fully endorsing it, which Apple Music and Pandora are de facto following.
In addition to R. Kelly, Spotify pulled the music of XXXTentacion, a rapper charged with multiple domestic abuse felonies, from its curated song collections. At the moment, he remains on Apple Music's playlists, and it's unclear which other artists may run afoul of any of this -- or other -- service's policies.