Apparently what didn't go viral was GWB's greeting of all 4 sets of people.
After greeting the Trumps Bush leaned over and did the same with the 6bama's, THEN he went around to the FRONT of the pew and greeted the Clinton's and the Carters.
It was the only physically polite way to do it. Bush did it, Trump chose not to.
Not EVEN the behavior of a 4th grader.