I actually support conscription. I think that a country has a right do conscript citizens to military roles (or civilian tasks) for the sake of the defense of the country.
But military (or civilian) service does not necessarily contribute to the defense of the country, or to the public good. Many wars and military operations are waged for reasons entirely different than national defense. Overthrowing Qaddafi (as evil as he was) had absolutely nothing to do with defending the freedoms of United States citizens. I have no more liberties now than I did before he was overthrown. However, I'm sure the people who had an interest in setting up a central bank in Libya are quite better off. But that isn't a good reason for me to go take the lives of other human beings.
I believe it is my right to not be forced to contribute to the killing of over human beings to protect the financial or political interests of others.