It's funny you say Robert Greene, because I've been listening to The 50th Law on my walks recently having read everything else he's written (save the 33 strategies of war).

He says so explicitly in interviews while admitting he lets himself get into a dark headspace to write because it creates a more interesting write/read. I think it's more of a style/pragmatic choice than anything, and an effective one, but he does command the reader to try-on the darkness/strategy. His books aren't going to corrupt anyone who wasn't already corrupt though imo. ime they're great for building intuition about sneaky people and learning more about what people truly want without the risk of dying of boredom.