Many young people don't always know why they make certain choices, to go to college, to war, to follow Phish. Often, in fact they find out down the road they wish they had made a different choice. One need not, then, have served in the military to make judgements about military matters, as those decisions are made in youth, on the advice of parents, teachers, and a host of other influencers. I think there's an argument to be made that civilians, both current and lifelong, may be better qualified to make final judgements about going to war - they may be better and more broadly educated, they don't have as much potential for bias towards particular branches, divisions, or individuals within the military as a whole, they haven't been "scarred" by emotional trauma that, due to its personal and tragic nature, is not helpful in rendering sound judgement on use of force.
I gather you disagree, and that's fine. I think there's plenty of genuine hypocrisy worth pointing out, and there may be some who fit the chickenhawk description. But it's not fair to use a bunch of dopey, MTV-addled teenagers as examples of the larger pool of Iraq war supporters who don't/didn't serve in the mlitary. Use them as cause to raise the voting age, maybe.