Gallows humor is a popular go-to for multiple popular internet fora. The topic was also brought up by a few influential YouTube science explainers (here's Kyle

Gallows humor is a popular go-to for multiple popular internet fora. The topic was also brought up by a few influential YouTube science explainers (here's Kyle Hill semi-apologizing for popularizing the meme: https://www.youtube.com/watch?v=z497lu4t5XI https://www.youtube.com/watch?v=z497lu4t5XI, although I don't think the Google Search history suggests his 2017 video was the primary mover of the popularity spike). In addition to the aspect of its horror that you highlighted, radiation is also a go-to science bogeyman because how how cause and effect are perceptually disjoint. You can feel absolutely fine absorbing way past an LD50 of radiation at the moment it happens; the suffering comes later, from hours to days later. Like firing up a computer with an already-damaged hard drive, you won't have a problem until the OS needs that data and loads garbage instead of useful routines.