Ask HN: How is Spotify filled with so much spam?

Earlier today I noticed a few songs had been added to a playlist of mine...with a bunch of "songs" by this artist: https://open.spotify.com/artist/68mk8GNhUjTLMw72RCBIvV

With a little exploration you run into an endless supply of bots, all with >1,000,000 active monthly listeners. At first I was pissed someone could not only randomly find my playlist and randomly add songs, but now I'm just wondering how it's possible for a service as able as Spotify to be filled with so much spam? Has anyone else experienced something Similar?