It's unfortunately true that many people feel that speaking in public is like walking barefoot on hot coals. You can actually see their discomfort. They can't stand still. They constantly shift their balance from one foot to the other and back again, like marching in place.
For others, standing in front of an audience is like facing a firing squad. They plant themselves on a spot and freeze, afraid to move an inch in any direction or they might get shot. Or they hide behind the lectern or podium, afraid to move out from behind its protective shield to get close to their listeners.