I watch these programs to inform myself.  My DH is 19 years older than I am....in fact he was in boot camp when I was born so I have no memories of Vietnam.  I try to learn as much as I can by tv or books and researching on the internet.  I feel the more informed I am the better equiped I am to understand/help him.  Luckily I have been a history fan all my life.  Maybe that is why I had such an interest in my "older" man....LOL  My DH can watch these shows one day and be fine but the next it bothers him.  I'm not sure I will let him know that they are on.