Are you holding them blameless? If so, why? This is the largest employer in the US and to not hold them responsible would imply they don't have the leverage to change the playing field. Of course they do.
Absolutely. We've somehow decided that businesses are entitled to enjoy the benefits of workers having enough money to live (i.e. large pool of willing, living employees, who are probably not going to die for lack of basic necessities before their shift tomorrow), with the public picking up a good chunk of the tab.
That's a subsidy. Every welfare dollar that helps a Walmart employee stay alive and go to work tomorrow is a gift from the taxpayer to Walmart shareholders: they'd have to pay for it if we didn't.
You the tax payer are already paying for this in the form of food-stamps and social programs that allow companies to benefit from well-fed, capable workers, while paying less than living wages.