They can’t stand to see someone “undeserving” do as well as or better than them, so they try to mow it down.

in australia and new zealand we have a concept called “tall poppy syndrome” (people who stand out from the crowd, who promote themselves excessively and publicly) and the reaction to that: “cutting down the tall poppy”. cutting down the tall poppy originally meant just bringing them back down to earth, but kinda morphed into simply criticising anyone that does well

we tend to have a relatively strong egalitarian streak, and perhaps that change was tearing people down rather than distributing their success to equalise

anyway, related: tearing down the tall poppy, ie pulling down anyone that stands out