That authority you decry simply holds the truths given by God to His Church.
Simple checks - where divorce and remarriage is allowed, is God’s law being followed?
Where sex outside of marriage is allowed or even celebrated is God’s law being followed?
Where contraception is allowed or even promoted, is God’s law being followed?
I apologise, I will be back later this evening and can continue our reparteé (pardon my French) then!