Let's see if I can shed some light on this.....
My family came to this continent in the 1650's. In that time, every male colonist had to be a rifleman, because his shooting skills to a large degree determined whether or not his family regularly ate meat. It also determined whether the community would be safe from not-always-friendly natives. Those riflemen then ended up forming the militias that fought with Britich Regulars in the French and Indian War and then the Minutemen who stood up to those same British Regulars.
During the American Revoution and War of 1812, most of the Amercan forces were Citizen Soldiers, who brought their own weapons and equipment to the battlefield. Even during the Civil War, the more American side (the South) was largely armed privately rather than by the Government. After the Civil War, the Department of War assisted in the creation of the Civilian Marksmanship Program (CMP) which still exists to this day, to help keep civilians competent in marksmanship skills in case of war.
After the Civil War, the American Military became more professional, but still depended on volunteers rather than conscripts for the most part. Very few Americans today who have been her for more than a generation or two cannot find a US Military Veteran in their family. As Americans we are proud of those who choose to give of themselves and serve. We are also through thanking those individuals thanking all that have come before them and all who will come after them.
Americans are "Pro-Military" because most of us understnad where we would be without that military. We understand the sacrafices those men and women make, and the traditions they uphold. We know those Soldiers, Sailors, Airmen, Coastguardsmen and Marines WILL be there when this nation needs them again.
THAT is why Americans are so proud of our military and why we consider our men and women in uniform to be such heroes.