To take your points in order:
(a) What a lame excuse. If we avoided topics that we could do nothing about, these message boards would contain about one tenth the posts they do now. At least have the guts to say that you’re torn between the choice of appearing to be a homophobe, and appearing to criticize the military. For what it’s worth, i suspect you’re not a homophobe.
(b) What fight? This is just a debate like any other. If you really had no desire to address the topic, why bother responding to the thread at all?
© See (b), above. When someone responds to a thread, it is generally assumed that the person is willing to address the issues raised in the OP, and to become involved in a debate. As for picking a fight with you specifically–don’t flatter yoursaelf. I’m simply pointing out where and why i disagree with DADT and those who support it. Same technique that most Dopers use in most threads.
While you might not have directly compared gays to deserters, all you did in your first post was point out how DADT gave some people an opportunity to punk out of the military. So, while you claim not to want to address the topic, your own first post did address it. You just punked out on drawing the logical conclusion that arises from your own post, which is: Get rid of DADT, and you not only rid the armed forces of a bigotted rule, but you close a loophole that is allowing people to leave the army early. It’s a win-win.