Why is this "Golden Comp" a "stealth campaign" but the Chronicles of Narnia are just good reading?

Although the Chronicles of Narnia contains pagan characters, the storyline is the story of the Gospel. Aslan is Jesus, the children are his disciples (but Edmond is Judas), the two girls who came to witness his execution/sacrifice are the women at the cross who mourned him; the White Witch is Satan, who gloated with his followers at Christ's crucifixion; Aslan/Christ was then resurrected from the dead, to return to destroy the white witch/Satan. This is not surprising given that the author was Christian.