Hardly irrational, and it's not a personal fear of change, it's knowledge of the shit storm that accompanies change that people aren't ready for at this point in time. Plenty of change is already afoot, how about we take a step back and tackle some of the more pressing current issues before addressing DADT?
The problem isn't with the opinions of the handful of homophobes in the military (yeah right, handful) in the matter of whether or not DADT is necessary or right, it's the structure and mindset of the military that makes the military work. The military is a man's world. Living quarters are tight, showers and restrooms are communal. It seems like what you're saying is that the politicians and decision makers should ignore the will of the soldiers (the homophobes, and this is regardless of whether they were homophobes before joining the military) and make decisions from the safety and comfort of their offices in Washington. The men and women in the field will have to live and serve according to these decisions. Their opinions should count for more.
"The majority of Americans under the age of 30 don't even understand why this is such a big deal." Did you take a poll about this or extrapolate from some data set? Have the majority of Americans ever served in the military and know what it's like to live the military lifestyle? I'm guessing you learned all you need to know about the world in college textbooks and from watching the news (and listening to radio talk shows).
This coming weekend should tell you all you need to know about America and it's understanding of military service. Memorial Day is all about barbecues, parties, and trips to the beach. The people serving in the military will have to deal with the decisions people like you make between bottles of beer. Hope you have fun this weekend, Ryllharu.