There were indeed people with PTSD after WW2. Many who were unable to function in society for years...even a few who snapped and killed people. I think the difference is that it wasn’t an “unpopular war” in people’s minds, so the media didn’t make a big deal out of it...and when veterans did snap and kill people it was treated as local news, without the if-it-bleeds-it-leads sensationalism we’ve been seeing since Vietnam.
I suppose you are right.