Well, he does make this opening statement: "In all my classes i stopped all forms of excerising. Classes begin with basic drills and move into techniques of the day." Clearly, if basic drills and techniques amount to exercise, then he had to be referring to a non-martial arts warm-up.
In any case, I tend to agree with you about burning up the hour doing calisthenics. Where this is really noticeable is with regard to seminars. I have to believe that few students are keen on paying for a two-hour seminar with an esteemed instructor who has been brought in from some distant location - only to find themselves doing a half hour of calisthenics.