I don't know about sucked up...i think during ww2, when they had seen millions dead and moving bodies off the roads with bulldozers, they felt like they had seen enough death. That and they had just reached normalcy after ww1, so that level of devastation was still quite fresh to them. 

Vietnam definitely changed their generation, to come home to be spit on and beat with bats and disowned by their townships, left many to deny they were actually in the service until many years later. There are however, a few vietnam vets whom had rampages of epic proportions. 

I hope one has to endure those 2 types of wars again (although it is inevitable), society would be in for a huge awakening while the brave answer the call to serve.