Sin is disobeying God's Law, not the mandates of a man-made religion.
And the RCC claiming that it has authority given by God to decide what is and is not sin is blasphemy.
The *church* can't just make up rules and then claim that disobeying them is a sin. What a corruption of the teachings of Jesus. What a hideous control tactic. Claim authority from God to determine who they let into heaven and who stays out and then threatening anyone who doesn't comply with eternal damnation of their soul.
The biggest irony is that Catholics are the first ones to shriek about how Protestants can't say who is saved and who is not and not only do Catholics do the self-same thing, but actually go on to tell others that they not only have the power to say who is saved and who isn't, but they even claim the POWER to determine who gets in and who doesn't.
They put themselves in the position of telling God what to do.
What an abomination before God.
Power corrupts and absolute power corrupts absolutely. That probably explains most of Catholic church history.
Sure she can.
I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose upon earth, it shall be loosed also in heaven (Mt 16:19)
Direct mandate for Christ to legislate in matters pertaining to salvation.
Further, that mandate was exercised according to the very scripture you pretend to believe:
I judge that they, who from among the Gentiles are converted to God, are not to be disquieted (Acts 15:19)
And thus, by a decision of a Church council, the Biblical law of Moses became null and void.
Bind and loose.