Heston wasn't so different from the Hollywood of old. Lee Marvin was a Marine sniper and got a purple heart. Douglas Fairbanks was a highly decorated Navy officer. Henry Fonda was in the Navy and got the Bronze Star. Clarke Gable flew five combat missions over occupied Europe. Eddie Albert had a Bronze Star. Tyrone Power was a Marine. And Jimmy Stewart was a highly decorated pilot and flew 20 combat missions.
Heston was just a holdover from an era when Hollywood wasn't full of spoiled, drug addicted, self-centered brats.