I didn't watch the interview; I gave up on the when she said it, on foreign soil.
Entertainers, like ex-Presidents, should not go abroad and bad-mouth our country or our elected leaders, especially in times of tension. Domestic politics should stop at the borders of their country. I believe that what Maines did was worse than Michael Moore's outburst at the Academy Awards.
That having been said, I don't hold the tasteless cover shot against them (except for the airbrushing ;-) in a moral context; let the market decide whether it will hurt or help them. It's not right to bare the bod for bucks, but Hell, it works for Madonna (I don't have any of her CDs). They're laying up treasure in the world they've chosen...
I think someone has made a lot of bad decisions -- either the Chicks or their handlers. They blew it on stage, and they've dealt with it poorly ever since. But then again, the only thing that would have brought me back into their fan base would have been a complete and simple apology, along the lines of, "I was wrong to get into my personal politics before a foreign crowd; I'm sorry I said it, and I promise that I'll always support my country in the future when I'm abroad." She's entitled to her views, and she's free to state them here at home (as we're free to make that part of our buying choices).
But let's face it, we're not going to hear any real apologies on the real issue from her -- she simply doesn't understand the "real issue."