I like listening to my dad tell stories from his time in the army. One thing he observed is that the drill sergeants he had were very much like the drill sergeants you see in the movies: insulting, swearing, and strict almost to the point of abusive. And he saw why. Although my dad was a married, returned missionary with 2 kids when he enlisted in the army, the rest of his group were 18 and 19-year old boys. And they acted the part. The primary goal in basic training is to crush you and try and get as much of the silliness and horseplay out of you as possible.