How is unfaithfulness to their vow to the Church any kind of insult against priests?
When for many reasons which would be good discussion items, the priest no longer "believes" in the effectiveness of celibacy either for himself or for his service to the Church, there arise an integrity problem. He continues to believe in service, but celibacy as a control mechanism or as a source of scandal because it is not observed, loses its value. The service of many dedicated married Protestant clergy is as great if not greater than that of the priest ( They usually do not spend as much time on the golf course, however).
For those who know not the life of the priest, to quote canon law, tell them they are unfaithful, thump the bible at them is treating the priests as though they were disobedient children rather than adult men.