Answer:
Twain refers to the Sunday School to lampoon the role of the church in society.
Explanation:
Twain's texts are full of criticism and he often satirizes important institutions. In the case of the text presented in the question above, it is satirizing the role of the church in society. This makes him mock the Sunday Schools, as they represent something worthless, where many students do not like it, but they appear out of obligation and for fulfilling the role that is expected of them, but they do not feel a connection either with the school, nor with the that is taught in it.
