It may sound corny, but what's wrong with wanting to fight for your country? Why are people reluctant to use the word patriotism?
Good questions from a famous American who was also a hero of WWII.
Maybe the fact that "patriotism" has come to be equated with putting a flag pin/decal on your lapel/vehicle/whatever, and considering it done.
Maybe the fact that "American exceptionalism" is one big 'hoo-rah!' for a country that isn't perfect, but can't seem to admit to making mistakes. [Especially in history textbooks!]
Maybe if teachers were allowed to teach that patriotism is doing one's best to help make your country a better place [volunteering, voting, becoming educated on issues, taking part] instead of just declaring it the best already, more people would try to be patriotic.
Conservatives don't allow textbooks to tell both sides of any story, and let students decide which they think was more reasonable - they require textbooks to teach history as an unending progression of progress, with good decisions all the way. It's nice to think so, but it's not true. How can we expect students to learn from mistakes, if they never hear anything about them?