Why does Dante dislike Eileen?

Dante dislikes Eileen because she isn't Catholic.... she is Protestant.

Stephen looked with affection at Mr Casey’s face which stared across the table over his joined hands. He liked to sit near him at the fire, looking up at his dark fierce face. But his dark eyes were never fierce and his slow voice was good to listen to. But why was he then against the priests? Because Dante must be right then. But he had heard his father say that she was a spoiled nun and that she had come out of the convent in the Alleghanies when her brother had got the money from the savages for the trinkets and the chainies. Perhaps that made her severe against Parnell. And she did not like him to play with Eileen because Eileen was a protestant and when she was young she knew children that used to play with protestants and the protestants used to make fun of the litany of the Blessed Virgin. Tower of Ivory, they used to say, House of Gold! How could a woman be a tower of ivory or a house of gold? Who was right then? And he remembered the evening in the infirmary in Clongowes, the dark waters, the light at the pierhead and the moan of sorrow from the people when they had heard.