Military service is the ultimate endorsement of the concept that your government knows what's best. Otherwise why would it be worth the potential sacrifice of your life?
Those who serve are frequently brave and noble. That does not mean the causes in which they are expended are always equally so.
Honor those who served, for the reasons they thought they were serving. Cherish the times it was true. But never deny that not every call to arms really manages to serve a higher purpose and a better future. In a better future we wouldn't spend so much time trying to kill each other.