WWII was a different kind of war. Everyone was involved. My grandma even worked in a steel mill. No one was against the war, how could you be? Later wars were smaller and not "world wars". The reasons for fighting in Korea and Veit Nam were different. I'm not arguing for or against them; I'm just saying that they are different than WWII. Many of the people you mentioned were drafted, so they had no choice. Others joined because they knew they would be drafted. I'm not saying that to lessen their service to their country.
Today actors are political activists. Would you want Richard Gere going to war for this country? Don't forget people like Tillman (sp?)- the pro football player who died in Iraq. People do care, just fewer than the WWII era. We haven't had a draft since Viet Nam, so only volunteers join the military. Some join for the wrong reasons (money, job, etc). You have to take the oath seriously or not at all.