But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed. Galatians 1:8-9
Neither Christ nor the apostles taught things like the assumption of Mary, the perpetual virginity of Mary or veneration of her. Neither Christ nor the apostles taught that we should pray to saints or Mary or that Mary would be the queen of heaven. What the RCC teaches is another gospel and our love for those who are truly seeking God demand that we persevere in our efforts to promote the truth of scripture.
That IS our job #1. Jesus did not say go into all the world and talk about yourselves. He gave us/them marching orders to spread the Good News about God's plan of salvation. He gave us the promise of eternal life with Him, through simple faith. Not works, not bowing and praying to graven idols and images of saints and women, but simply to place our trust in Him.
John 3: 13 No one has ever gone into heaven except the one who came from heaventhe Son of Man. 14 Just as Moses lifted up the snake in the wilderness, so the Son of Man must be lifted up, 15 that everyone who believes may have eternal life in him.
16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. 17 For God did not send his Son into the world to condemn the world, but to save the world through him. 18 Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of Gods one and only Son. 19 This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil. ...
John 12: 42... But because of the Pharisees they would not openly acknowledge their faith for fear they would be put out of the synagogue; 43 for they loved human praise more than praise from God.
... 44 Then Jesus cried out, Whoever believes in me does not believe in me only, but in the one who sent me. 45 The one who looks at me is seeing the one who sent me. 46 I have come into the world as a light, so that no one who believes in me should stay in darkness.
Neither Christ nor the apostles taught that we should pray to saints or Mary or that Mary would be the queen of heaven.
Details... the devil's in 'em.