I contemplate why this comic would never happen

Is anyone else confused about this timeline? According to something actually reputable I read here on the internet, smallpox vaccinations were routine in the United States until 1972. Up until then, it was recommended for all children at the age of one. So technically a person born in the U.S. as late as 1970 or 1971 could have been subject to routine vaccination. That would be make said person nearly forty years old now. And while, obviously, it is possible for a forty year-old or younger person to be a grandparent if they had children young and so did those children even without having gotten pregnant while technically still in high school, I do not think this is usually the demographic Pluggers is meant to represent (they're supposed to be OLD). Also, which "war" would we be talking about in this case? The Persian Gulf War? I'm pretty sure that never happened. Let us consider a different timeline. When someone asks "Grampa" about the "war," I myself think of World War II. Both of my grandfathers served in the Navy during that conflict, and one of them also served in Korea. I know a bit about my maternal grandfather's war experiences in the Pacific mostly because my mother is both nosy and a gossip, which I love and is incredibly valuable in picking up family history tidbits. However, I NEVER would have asked my grandpa about the war or where he got a specific scar. Maybe that's because we don't talk about personal things in my family or maybe because I'm pretty sure I was never in the room while he was shaving because that would be weird and we don't do that and also my grandparents are all dead. But really, to be a WWII vet, this dog-man would have to be, at the youngest, about eighty years old. And if his family reproduced later in life, he could perhaps have a grandson about eight years old or so (I'm guessing from this illustration, I don't actually know how Plugger men-beasts age). But do eight year-olds know much about WWII? Maybe if they watch the History Channel a lot. I mean, I remember reading stuff about the Holocaust in about fourth grade or so, so I'm not really sure. But would a child of that age really have a good conception about what it means for a man-dog to go to war and possibly be injured, and transfer that association to his own family member, when it happened several decades before his birth?* But what is probably most likely in the generational timeline featured here would involve a grandfather who served in Vietnam, in which case, unless you are the grandchild of great American Hero John O'Neill who I know way too much about and who just can't stop talking about Vietnam, I don't see a kid knowing that much about it. See, even in my AP U.S. history class in high school, we covered the Vietnam War by reading a couple chapters and watching some TV specials about the sixties or something. Because, you know, it was all controversial and we lost our national manhood by losing there and blah blah blah. Not as many heroic movies made about it. So what I'm saying is, what child of this age would be all cognizant of all those issues listed in the WWII example and connect them to their own grandfather who probably doesn't really want to talk about "the war," if anyone ever mentions it at all? These are the various assumptions I'm bringing to the table here about why this scenario is unlikely in the first place. Also, Gramps' response doesn't really make sense. And it's not funny. Also, dogs can't get smallpox, though they can go to war. *I will concede that if a Plugger-child were to have an immediate family member CURRENTLY serving in one of our current overseas military clusterfucktastrophes, he or she would likely have a better grasp of these issues than the average child.