Yeah just as SumProVita said, that quote from St Augustine isn’t saying Mary has the power to forgive sins. He (Augustine) is saying she was given a special grace to resist sin. In other words, the Immaculate Conception, which miraculously (through the power of God, via Jesus’ sacrifice on the cross) preserved her from Original Sin, which also preserved her from what we Catholics call “concupiscence”, which (in the Catholic sense) is a tendency to want to sin, or to resist holiness. (Not merely a tendency to commit sexual sins as the definition implies.).
So there is no blasphemy here per se. (Not in what St Augusinte really said.). Of course, others argue that the Immaculate Conception never happened at all, to which I will depart from this conversation.
Mary was equally in need of forgiveness as any other woman....she was not sinless. To elevate her to the extent catholics do.. and it’s teachings concerning her... is an offense to Jesus Christ for He alone is to be worshipped, bowed down to and adored...and prayed to.
Your reasoning is like liberals ....you invent some off handed idea of who Mary is in your minds, contrary to the truth God has declared, because to accept the truth would mean you’d have to face your errors and examine everything else about the catholic church they indoctrinated you with.
It’s much, much easier to carry the banner of the “we catholics” rather than the banner of the Cross of Christ and His gospel message front and center... that there is salvation and forgiveness found ONLY in Him....not in a church denomination that makes false claims about itself and misleads the masses it needs to keep it’s coffers filled and it’s power in Rome alive.