Yeah, the point of the joke is that crop rotation has been practiced for literally thousands of years. It was an agricultural invention which gave ancient cultures significantly higher crop yields, enabling a huge number of societal, cultural and scientific developments. The joke is based on the idea that before crop rotation was discovered, some people might have considered it a silly idea, delaying the developments enabled by the significantly increased crop yields.
I’m not as against these “sad narratives” as you are, but I still think that this one just doesn’t make much sense. Photons hit random planets and stuff all of the time, so arguably hitting a living sentient being is one of the coolest things that could happen to a photon.