This is simplistic of course, but roughly accurate; paychecks represent a claim on a finite amount of national production, and at least part of the reason that steelworkers could be paid so much, is that blacks, and particularly women, were paid so little for the work they did.
Is "accurate" a synonym for bullcookies? How could The Economist spew such silliness? Steelworkers were paid what they were paid becaue they could extract their wages from the process, i.e., a pot of money made in the steel industry, not because there's a national pot of money that they kept black's and wimmin's fingers out of. Now, if you want to complain that these Democrat interest groups kept blacks and women out of the unions, fine.