In the article by Courtney Cutright, "Boy Scout Jamboree facility a huge project for Rockbridge County", there appears to be some confusion over terminology. Usually a "stadium" is "A large, usually open structure for sports events with tiered seating for spectators." An "amphitheater" is generally "a level area [stage] surrounded by upward sloping ground."
In Boy Scout parlance, an amphitheater is a flat stage area with gently sloping, grass-covered ground (no seats) usually less than half-way round the flat area so that everyone sits, more or less, on one side facing the stage. In 1964, such was the case when I attended the National Jamboree held at Valley Forge, Pennsylvannia.
Most Scout Camps have such an area though they are provided with bench seats usually hewn from logs. The amphitheater for a National Jamboree does not provide seating (save for the ground) as having seats with the resulting aisles would increase the time for the thousands of attendees to enter and egress.
I am rather surprised the Scout Executive making the presentation did not address this issue. Or, were the stadium seating data added following the meeting during the article preparation?