Don't believe what you read on the internet or see on TV. Most of those who served in Vietnam lived a relatively safe and routine life. They were safely ensconced on a secure base and provided administrative and logistics support to the war. A small minority lived "outside the wire" and fought, not the Viet Cong, but the Regular North Vietnamese Army. But all of them were in the combat zone and were expected to defend themselves and to contribute to the fight if required. The guys behind the wire did not want to wander out there in bad guys country. The guys out in the bush wished that they had learned how to type.
These people are called Vietnam Veterans. Blumenthal is not among them.
I would put a lot of emphasis on the word "relatively".
I spent my time "behind the wire" for the most part. The greatest risk I probably faced was getting killed or injured in a vehicle accident. I've never seen the actual numbers but have heard that a very high number of troops died in "non-combat" accidents.
Next in line to that might have been a form of "friendly fire" caused by high numbers of unhappy, hard-drinking (or drugged up) troops.
Finally there was some risk from disease. Not that long ago there was a medical alert sent out recommending that Vietnam Era Veterans get tested for hepatitis. Despite having not been a drug abuser, I found through testing that I had naturally occurring immunity to hepatitis A and B. Some believe that the air-gun vaccine injectors were responsible for spreading blood borne diseases. It's also possible that I contracted hepatitis from finding myself taking care of biological necessities while being in ankle deep sewage for weeks on end.
I think that I have read that every soldier in combat requires five or more soldiers behind the lines for support. I spent a lot of time on guard duty; ready to face whatever arrived. I once spent 17 hours one day without a break. I was very fortunate that the enemy went elsewhere.
I would guess that some of the veterans who returned having faced violent combat consider themselves very fortunate compared to those who were killed or seriously injured. I don't think it is as simple as those in combat and those "behind the wire".