Odd positions. The main reason the protesters are even out there is they are bringing up the issue that WalMart pays so low that the taxpayers end up subsidizing the WalMart workers anyway, foodstamps, etc.
But that of course if one of the unintended consequences of providing unearned benefits to people who could potentially be working. Once you have government supplied benefits to people with low incomes, the labor market adjusts accordingly. For those workers, low income isn't really the same as low wages since their actual income is the sum of what they are paid at work and their government benefits.
In many states a single mother needs to earn close to $50,000 before her earnings match the value of her government benefits. But there aren't that many jobs, and certainly not many in retail stores, which can support that kind of salary without adjustments throughout the economy.
If there wasn't a pool of potential workers who rely on their government benefits, and a steady supply of immigrants willing to work for low wages and receive government benefits, then the market would adjust to pay higher wages since they would be necessary in order for employers to hire the workers they need.
Perhaps a more effective way to increase wages at Walmart would be to reduce the availability of government benefits, and reduce the costs associated with healthcare and taxes.