I have no problem with that and in fact admire it. But we've allowed our minimum wage to be too low, and they have competition and of course cannot compete if unilaterally raising pay. So that's our job, via policy.
And in my opinion, the DC proposal is stupid. Raise the minimum wage to $12, so more consumers offset the higher pay. But targeting only certain retailers, turns it into a flat-cost calculation, and might be good politics (leveraging foolish Walmart-disdain) but stupid economically. Wage increases have to be across the board to work effectively.