Some were brought up to hate Catholics and cannot change.
I was not raised around Catholics so I literally have no opinion of them. However, when Jesus died upon the cross, the tapestry in the Temple separating the Holy of Holies from the rest of mankind was torn in two, symbolically removing the priest from between man and God. Neither Mary nor any of the saints can do a thing for you unless they do it through the power of God. To pray to ANY deceased or living human being other than the one Son of God, is to raise them to the status of God and therefore to make THEM a god.
Also, read the bible ANYWHERE that an angel appears. What is the first thing the angel says? “Be not afraid.” And when the human falls to their feet, they say, “Get up, I am not God. Do not worship me.” You won’t hear Obama saying that, will you?
And, manage to somehow square up that hatred with their faith in God and Christianity.