You shouldn't get your news from corporate media. Corporate media don't like unions because they fight for living wages which cut profits from the few who benefit from them.
Economists don't like protectionist unions. Who determines a "living wage"? Should someone working as a cashier in Walmart be able to afford an apartment in Manhattan?
Someone working as a cashier in Walmart should be able to afford shelter, food, and necessary non-emergency medical expenses. A 'living wage' is just that -- I work for you, you pay me at least enough to survive employment. What that amounts to, obviously, depends on the standard of living in any particular area.
If it's impossible to survive in (or on, whatever) Manhattan for less than that, then yes. But I suspect there's a more flexible reality to the market than your question implies, given that people there already work for less than that and aren't dying in the streets as a result.
A minimum wage just means you can't decide one day that sales are down and now everyone makes 2 cents an hour to cover costs [1]. It means there should be an implicit minimum cost to maintaining a human workforce, because people need to eat.
If Wal-Mart had to pay a "living wage" (and who defines what that is? Certainly not the worker.) they would not exist. You may think that's good, or bad, but most of the Wal-Mart jobs would not exist at all if they were forced to pay an artificially high wage to their employees.
In Australia in the past there was a national industrial court that did this. In Germany regular courts did something similar. Courts are expensive, so why not use a computer program from MIT:
> most of the Wal-Mart jobs would not exist at all if they were forced to pay an artificially high wage to their employees
People would still buy things. Something like this happens:
> With minimum wage laws, the increased costs are passed to employers who in turn charge consumers higher prices if possible. Faced with higher prices, consumers purchase fewer goods thus leading to a redistribution ....
By artificial I mean "different from a market outcome".
There is quite clearly an asymmetry in information and market power between Wal-Mart and individual employees.
This will inevitably lead to artificially low wages.
So raising them with a law will return them to a free market level, where free market implies complete information, interchangeable goods and services, and lack of market power