Agreed. There were over 58,000 killed in Vietnam and no president could call all of those families.
While President Trump has many good qualities, one of his least admirable traits is the tendency to cast everything he does as being bigger, better, or more virtuous than anyone else.
Nonetheless, all of those 58,000 men were precious to their families; they weren't Kleenex to just be expended and forgotten. Maybe if the President was required to express condolences to the families for each death, there wouldn't be as much wanton waste of life. He'd have been really busy during the weeks of Operations Hastings and Prairie and during the battle of Hue City.
I still visit the families of the friends I lost in Vietnam.