Because in the english language the phrase "Labor Creates all Wealth" doesn't make obvious sense because it's not clear what "Wealth" refers to. It could mean "labor creates all of rich people's money" or it could mean "Labor creates the wealth of society", but what is the wealth of society? It's an indeterminate term. Saying that Labor builds society is more straightforward because that's what we're talking about, how workers have literally been the ones to build society and the ones that keep it going through their jobs.
first sale 5/30/09
From a sharpie pen drawing I did and colored it in Photoshop.