You do not know that Hillary said nothing about WalMart's union busting, only that she did not change the company.
By the way, you should know that corporations often appoint popular celebrities to their boards to show the public how in touch they are with the hoi polloi, but the board is divided into at least two groups: the Executive Committee of the Board of Directors meets in executive sessions in which the other directors are excluded. That is where things like employment policies are discussed. The celebrities on the board decide who gets to light the Corporate Christmas Tree, and who gets to receive charitable donations. They get to be photographed handing out awards and plaques and brobdinagian checks. The members of the Executive Committee of the Board do not like to be photographed. It means that they need to pay more for bodyguards, among o0ther things.
Corporations, in reality, are run far more like Stalin's Kremlin than like the House of Commons. I see Hillary as better than any of the total sellouts that the Republicans have vying for their nomination, but I like Elizabeth Warren and Bernie Sanders a LOT more than Hillary, especially when I consider what they might accomplish. Campaign promises are never implemented fully, because of the way our rather archaic and ossified system works.