I am guessing the artist who did this image did not ask for permission of the dead soldiers families to make this political message:
I hate Bush with a passion. But I do not think it is right to use the deaths of specific individuals (or their images), without their families permission. This one isn't so bad, is it's just the flag draped coffin, now specific soldier, but I do think that if the person died for something the believe, to twist their sacrifice around for political gain is wrong. But if the person had enlisted to protect America and felt being Iraq was a sham, then the family should know that and be willing to use the soldiers image for an anti-war message. I do not think just grabbing images of these people with out context of their desires and using them for a poltical end is right.