A theologian was part of the cast of actors. He had very little to say about chastity from the viewpoint of Sacred Scripture or theology. It grows stronger through practice. As facility in its practice increases, it yields a deep sense of inner tranquillity. Although chastity never becomes easy its practice becomes pleasurable in an exalted manner due to the freedom that it gives the practitioner.
Chastity is a supernatural virtue.
It is a gift given by God and is enriched with all the graces necessary for its practice. This does not exclude the effort that must be made by the practitioner. Unless the chaste person deepens his prayer life, practices mortification and humility, he will find chastity an impossible task. Perhaps the authors decided that the religious men in the United States knew all about the theology of the vows and were making use of this knowledge. Perhaps the authors wanted to add insights from psychology to make it easier for religious to live the celibate life.