While nowhere near GP's example, I come from a working class background where this metafor feels instantly fitting. Perhaps the middle ages made it so that groups who did not pull their peers back down died out / were killed by the ruling classes.
Really that toxic dynamic is also explained by reproductive habits - everyone not desirable for having X looks bad in comparison. It is a way deeper mental flaw in humanity along with rationalizing obviously terrible things to avoid cognitive dissonance and extra effort.