FWIW, Eastwood is an Army vet himself (not combat) and has been a Republican, as well. I think (within the framework of Hollywood..) he is a decent guy.
The bias most seen in Hollywood, among the artists, as opposed to propagandists (and I think Eastwood is among the former) is a bias towards the personal. Sometimes, as in war movies especially, they tend to overlook the extent to which individuals can be motivated by patriotism, duty and even history itself. They get too caught up in the personal. It's not necessarily inaccurate - after all, there can be no denying that men fight for their comrades- but it is distorted to pretend there is no other motivation. I have not seen this movie (yet) but I know the Hollywood meme.
Anyway, that is my defense of Eastwood, who I expect has given respectful treatment to the story, based on the book by one of the Marines' sons, as well as to history and to America. I look forward to seeing the film.
In Vietnam, 2/3 of the soldiers VOLUNTEERED. While some did it for thrills, many did it for the IDEA of liberty.
And surveys show that our troops in Iraq fully understand the ideas for which they fight---as well as "each other."
I just think Clint fell victim to a current "theology" in Hollywood that diminishes the role of ideas in human motivation.