It is not mere church law regulating the sacraments that is violated. Female priests destroy the fundamental nature of the relationship between Christ and His Church. That relationship is nuptual, when the essentially male energy of Christ penetrates the Church as they unite in one mystical body and produce the offspring of Christendom. The Church is essentially female in it as she is the nurturing mother to us and the obedient partner to the head of the household Christ the Bridegroom. A woman cannot marry Christ's church and cannot be a father to the flock, it puts the entire theology of St. Paul's epistle to Ephesians upside down.
Worse: It turns God into a lesbian.