No, "Harsher in Hindsight" is when art suddenly seems much darker in light of recent events. For instance, if you wrote a funny comic in the 90's about the World Trade Center being destroyed, it wouldn't be nearly as funny nowadays. That's the kind of thing that defines "Harsher in Hindsight". DDLC all came out at once, and this fanart came out well after its release. Even if the hanging thing was unintentional (which I'm not entirely convinced of- I think it's just a darkly comedic reference to the actual events of the game), it's not something that was made darker by new developments that have come out since the art was posted.
