Yeah, the whole notion of this being something generated with a markov chain feels too much like hype.
The guy admitted on reddit that he manually cherry-picked and assembled the lyrics, and then he sang and recorded the song himself.
For all intents and purposes, he might as well have just fed a bunch of AC/DC lyrics through a word randomizer and then assembled the new lyrics by hand. No AI or markov chains required.
On the other hand, here is ACTUAL real music generated and played entirely by AI: https://openai.com/blog/musenet/