I think some part of the problem is the left's failure to articulate the moral case for less income inequality. I'm amazed at how often I'm talking with demonstrably poor people who bitch about "all those layabouts on welfare," completely missing that their issue with it is envy - those "layabouts on welfare" are doing as well as the working poor bitching about them. It's pecking order, "yeah, well, I may be as poor as you are, but at least I'm not a mooch!" Society has let them know they suck because they are poor, so there's a real incentive for them to place someone lower on the totem pole Just a few days ago, I was talking to a poor woman was applauding the food stamp cuts. I couldn't hold back and told her I thought it was a horrible thing. I noted that most of the people on food stamps work but just don't make enough money to feed themselves. "And now," I said, "they'll be going to work hungry. That's not a good thing." The moral case for living wages is pretty simple: the great mass of humanity, usually through accident of birth, has no capital. They have only their labor with which to barter for the necessities of life. It's accepted that people like doctors, engineers, CEOs will make more money because of the investment of their time in education. But all of us have a finite amount of time on this earth, and none of us knows how much time we've got. So for each individual, time is a valuable, precious commodity. The moral formula is pretty simple: any day of work has got to provide compensation enough to support the individual who performed it (food, clothing, shelter) for a day. Otherwise you're expecting people to dig into the only capital they have - their life - and trade it away for nothing. It's immoral to ask someone to sacrifice their life - any portion of it - in the service of generating profit for someone else, without paying at least the amount that person needs for living during that period of employment. An individual wouldn't open a burger joint knowing that his return would be $7.35 per hour and that for each hour he was open, he would be falling further behind in terms of making a living; that his work would not just waste his limited time but actually buy him hunger. But turn that burger joint into a multinational corporation with rich people skimming profit off the top, and it's "just the way things are."
It's theft, pure and simple. People need to understand that wealthy corporations - specifically the wealthy people who own them - are stealing their lives.
*edit: I should add to this that what I've outlined is the answer to the "some people aren't worth more than minimum wage" argument. If a business can't run without them, or someone else in their job, they are essential and there is no business and no profit without them. If a business can't generate enough income to at base pay the people required to run it enough to live, then it is a business that should not exist, because no individual would undertake it on his own, knowing that it would do nothing but put him in an ever-deepening hole.