Wal-Mart shareholders acting through their board of directors have sole power to set wages for their 1.4 million US workers. If they chose to pay a living wage the taxpayers wouldn't need to provide $6.2 billion every year to Wal-Mart's labor force.WalMart doesn't have that kind of power. They may support and benefit from welfare programs, but the legislatures that pass these laws are the responsible parties.
Taxpayers don't "need" to provide anything to their labor force. They're forced to do so by government, not Wal-Mart.