The "chickenhawk" argument is dishonest. It is dishonest because the principle of republicanism is based on freedom of choice about behavior (as long as that behavior is legal) as well as freedom of speech about political issues. We constantly vote on activities with which we may or may not be intimately involved. We vote on police policy, though few of us are policemen; we vote on welfare policy, though few of us either work in the welfare bureaucracy or have been on welfare; we vote on tax policy, even if some of us don't pay taxes. The list goes on and on. Representative democracy necessarily means that millions of us vote on issues with which we have had little practical experience. The "chickenhawk" argument -- which states that if you haven't served in the military, you can't have an opinion on foreign policy -- explicitly rejects basic principles of representative democracy.
The "chickenhawk" argument also explicitly rejects the Constitution itself. The Constitution provides that civilians control the military. The president of the United States is commander-in-chief, whether or not he has served in the military. Congress controls the purse strings and declares war, no matter whether any of its members have served in the military or not. For foreign policy doves to high-handedly declare that military service is a prerequisite to a hawkish foreign policy mindset is not only dangerous, but directly conflicts with the Constitution itself.
The "chickenhawk" argument proves only one point: The left is incapable of discussing foreign policy in a rational manner. They must resort to purely emotional, base personal attacks in order to forward their agenda. And so, unable or unwilling to counter the arguments of those like Paul Wolfowitz, Dick Cheney and President Bush, they label them all "chickenhawks." By the leftist logic, here are some other "chickenhawks": John Adams, Benjamin Franklin, Thomas Jefferson, John Hancock, James Madison, Abraham Lincoln, Woodrow Wilson and Bill Clinton.
American soldiers fight for the right of all Americans, regardless of race, class or past service, to speak out on foreign policy issues. If they fight for the right of pacifist anti-military fifth columnists like Michael Moore to denigrate their honor, they certainly fight for the right of civilian hawks to speak up in favor of the highest level of moral and material support for their heroism.