I suspect it might be complicated by the fact that most of their content isn't owned by them but leased(?) from record labels, artists, podcasters, etc? But I

I suspect it might be complicated by the fact that most of their content isn't owned by them but leased(?) from record labels, artists, podcasters, etc? But I agree it seems like they use this API as a free launch pad for ideas, which seems morally or ethically questionable. Sorry to hear they might have ripped your idea.