The current euphemism for such envy from the left is "fairness." Perhaps the most telling example is Obama's statement in a debate that he would favor an increase in the capital-gains rate, even with the knowledge that no revenue benefit would result, purely in the interest of (his notion of) fairness.
The only real fairness is unfettered benefit realized from endeavor dedicated to providing for others at a profit moderated by market forces. Compassion for the needy is, of course, a moral obligation, but that is not fairness. And the moral obligation of the needy is gratitude and not envy.