What is devalued is traditional labor-based ideology. The blog references Marx's theory of alienation. The Marxist labor theory of value, that the value of anything is determined by the labor that creates it, gives the working class moral authority over the owner class. When labor is reduced, the basis of socialist revolution is devalued, as the working class no longer can claim superior contributions to value creation.
If one doesn't subscribe to traditional Marxist ideology, this argument won't land the same way, but elements of these ideas have made their way into popular ideas of value.
Marx addressed exactly this sort of improvement in productivity from automation. He was writing with full hindsight on the industrial revolution after all. I hope coding LLMs give professional computer touchers a wakeup call to develop some sorely lacking class consciousness.
>the capitalist who applies the improved method of production, appropriates to surplus-labour a greater portion of the working day, than the other capitalists in the same trade […] The law of the determination of value by labour-time, a law which brings under its sway the individual capitalist who applies the new method of production, by compelling him to sell his goods under their social value, this same law, acting as a coercive law of competition, forces his competitors to adopt the new method.
If one doesn't subscribe to traditional Marxist ideology, this argument won't land the same way, but elements of these ideas have made their way into popular ideas of value.